Co-authored-by: Georg Wechslberger <wechslbe@ma.tum.de>

Adds initial support for flutter create of apps and plugins. This is derived from the current FDE example app and sample plugin, adding template values where relevant.

Since the APIs/tooling/template aren't stable yet, the app template includes a version marker, which will be updated each time there's a breaking change. The build now checks that the template version matches the version known by that version of the tool, and gives a specific error message when there's a mismatch, which improves over the current breaking change experience of hitting whatever build failure the breaking change causes and having to figure out that the problem is that the runner is out of date. It also adds a warning to the create output about the fact that it won't be stable.

Plugins don't currently have a version marker since in practice this is not a significant problem for plugins yet the way it is for runners; we can add it later if that changes.

Fixes #30704

Adds utility code for managing list of plugin projects within a solution file, updating them as the plugins change.

This is a prototype of an approach to solution-level portion of Windows plugin tooling; it may not be what the final plugin handling on Windows uses, but it makes things much better in the short term, and gives us a baseline to evaluate other possible solution management systems against.

Part of #32719

[a11y] Make sure RenderFractionalTranslation updates its semantics after the translation field is set (#48985)

Revert "Check Xcode build setting FULL_PRODUCT_NAME for the name of the built app during flutter run (#47266)" (#47568)

This reverts commit 648a5d8a.

Check Xcode build setting FULL_PRODUCT_NAME for the name of the built app during flutter run (#47266)

Revert "Check Xcode build setting FULL_PRODUCT_NAME for the name of the built app during flutter run (#46928)" (#47264)

This reverts commit e54e301d.

Check Xcode build setting FULL_PRODUCT_NAME for the name of the built app during flutter run (#46928)

* 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 reverts commit 3597bae6.

...because otherwise, processes that think they're manipulating your
filesystem will be doing crazy things the test is ignoring, leading to
(at best) failures and (at worst) flakes or disk corruption.

Adds very preliminary support for Windows and Linux plugins:
- Adds those platforms to the new plugin schema, initially supporting just a plugin class.
- Adds C++ plugin registrant generation for any Windows or Linux plugins found.

This doesn't have yet have any build tooling for either platform, so anyone using the generated registrant still needs to do manual build configuration. This reduces the manual work, however, and creates a starting point for future tooling work.

As with all Windows and Linux work at this time, this is not final, and subject to change without warning in the future (e.g., Windows could potentially switch to a C# interface, or
'linux' may change to 'gtk' or 'linux_gtk' in pubspec.yaml).

We were using the `defaults` command-line utility to parse
Plist files, but it was never supported by Apple, and it
appears that in an upcoming OS release, it will be less likely
to work:

> WARNING: The defaults command will be changed in an upcoming
> major release to only operate on preferences domains. General
> plist manipulation utilities will be folded into a different
> command-line program.

Fixes https://github.com/flutter/flutter/issues/37701

Move tools tests into a general.shard directory in preparation to changing how we shard tools tests (#36108)