Updates the tooling to use the GTK embedding, rather than the GLFW embedding:
- Adds new requirements to `doctor`
- Updates the app and plugin templates to make GTK-based runners and plugins
- Stops downloading and installing the GLFW artifacts

Final part of #54860, other than cleanup.

Current versions of the Windows desktop build files don't require a specific Windows 10 SDK version, but doctor still checks for one since vswhere doesn't allow for flexible queries. This has been a common source of issues for people setting up on Windows for the first time, because the current VS installer by default only includes a newer version of the SDK than what doctor is looking for.

This removes the vswhere SDK check, and instead uses a manual check for SDKs. Since this uses undocumented (although fairly widely used, so relatively unlikely to change) registry information, the check is non-fatal, so that builds can progress even if the SDK isn't found by doctor; in practice, it's very unlikely that someone would install the C++ Windows development workload but remove the selected-by-default SDK from the install.

Now that all requirements are default, the instructions when missing VS have been simplified so that they no longer list individual components, and instead just say to include default items.

Fixes #50487

Updates the Linux templates to use CMake+ninja, rather than Make, and updates the tooling to generate CMake support files rather than Make support files, and to drive the build using cmake and ninja.

Also updates doctor to check for cmake and ninja in place of make.

Note: While we could use CMake+Make rather than CMake+ninja, in testing ninja handled the tool_backend.sh call much better, calling it only once rather than once per dependent target. While it does add another dependency that people are less likely to already have, it's widely available in package managers, as well as being available as a direct download. Longer term, we could potentially switch from ninja to Make if it's an issue.

Fixes #52751

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

This updates the flutter tool cache to download binary files for ideviceinstaller, ios-deploy, libimobiledevice, and dynamically linked dependencies from Flutter's GCP bucket.

This reverts commit 14d489ad.

This updates the flutter tool to cache binary files for ideviceinstaller, ios-deploy, libimobiledevice, and dynamically linked dependencies from Flutter's GCP bucket.

Moves the logic for finding vcvars64.bat to a new VisualStudio class
that encapsulates finding, and providing information about, VisualStudio
installations. Adds a validator for it, and runs it for Windows
workflows in doctor.

Splits Xcode validation out of the iOS validator and into a stand-alone
validator, and groups the CocoaPods validator with that top-level
validator instead of the iOS validator. iOS now validates only the
iOS-specific tools (e.g., ideviceinstaller).

Reorganizes many of the associated clases so that those that are used by
both macOS and iOS live in macos/ rather than ios/. Moves some
validators to their own files as part of the restructuring.

This is the macOS portion of #31368

The current repair command for Arch Linux is no longer valid because
`lib32-libstdc++5` had been removed from multilib.

Actually, `lib32-gcc-libs` from core just work.
Also see https://github.com/flutter/flutter/issues/25035

## Description

Also update the existing dart files with missing licenses.

Without the fix, we'll emit the following error message
```
License headers cannot be found at the beginning of the following files.

/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/lib/src/animation/tween_sequence.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/material/raw_material_button_test.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/async_lifecycle_test.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/sliver_constraints_test.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/app_test.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/test_border.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/physical_model_test.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter/test/widgets/inherited_model.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter_tools/lib/src/base/user_messages.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter_tools/test/src/pubspec_schema.dart
/usr/local/google/home/liyuqian/flutter/flutter/packages/flutter_tools/test/ios/simulators_test.dart
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
```

## Related Issues

Fixes https://github.com/flutter/flutter/issues/28368

## Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes (`[x]`). This will ensure a smooth and quick review process.

- [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
- [x] My PR includes tests for *all* changed/updated/fixed behaviors (See [Test Coverage]).
- [x] All existing and new tests are passing.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] The analyzer (`flutter analyze --flutter-repo`) does not report any problems on my PR.
- [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I am willing to follow-up on review comments in a timely manner.

## Breaking Change

Does your PR require Flutter developers to manually update their apps to accommodate your change?

- [ ] Yes, this is a breaking change (Please read [Handling breaking changes]).
- [x] No, this is *not* a breaking change.

<!-- Links -->
[issue database]: https://github.com/flutter/flutter/issues
[Contributor Guide]: https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Test Coverage]: https://github.com/flutter/flutter/wiki/Test-coverage-for-package%3Aflutter
[Flutter Style Guide]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[Handling breaking changes]: https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes

* Allow for gradle downloading missing SDK assets if SDK licenses are present.

*  Improvements for windows testing

This reverts commit 6f5e88a5.

* Allow for gradle downloading missing SDK assets if SDK licenses are present.

* Fix license path for missing sdkmanager

* Cirrus re-run...

* Fix condition check

* rename props, add docs, rename method

* fix tests after param changes

* Fix weird path for flutter run and add tests

* remove print, fix tests

* Refactor for iOS.

* For android_xxx_unopt_arm64&ios_xxx_unopt_arm, remove the _arm64/_arm suffix.
dart generated in host_xxx_unopt/host_xxx has an arch of x86_64 which supports arm64/arm.

* Remove suffixes for various archs.

Currently, in pubspec.yaml, semver.org is referred to for more about versioning.
However, the versionCode/versionName could differ on different platforms (iOS, Android, Dart).

This adds more clear and complete information that could help users to understand it better.

See: #27251