Adds initial support for `flutter create` of apps and plugins. This is derived from the current FDE example app and sample plugin, with a few changes:
- Added template values where it makes sense.
- Moved some likely-to-change values into separate files for now, to simplify the delete/recreate cycle that will be necessary until it's stable.
- Added some minor Makefile flag handling improvements

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whatever build failure the breaking change causes and having to figure out that the problem is that the runner is out of date.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.

This makes ephemeral symlinks to each plugin, for use by build systems.
This is similar to the logic implemented in the Podfile on iOS and
macOS, but managed internally to the Flutter tool.

Exploration for addressing #32719 and #32720
Related to #41146

Moves the checks that projects have been configured for desktop to a lower level, where they will cover more codepaths (e.g., 'run'), and improves them to check for native build projects, rather than just directories, to catch cases where the directory exists (e.g., due to accidental creation of generated files).

Also adds links to the error messages pointing to instructions on adding desktop support to a project.

Fixes #47145

* 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

* implicit-casts:false on flutter_tools/lib

* address review comments

* use castStringKeyedMap

* introduce {bool,string,strings}Arg

* fix ci

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas

Currently Linux builds override the default BUILD mode by putting it in
the generated config. That makes it sticky for manual runs of make,
which is inconsistent with how other platforms work.

Instead, pass the build mode as a command-line override, the same way
someone would if building directly with make. This makes the flow of
controlling the mode less confusing.

Fixes #41528

Moves the generated config into that directory. Matches the structure of
the other desktop projects.

Also fixes #40265

Fix some places where Debug/Release was treated as a binary switch.

Makes similar changes to Windows and Linux to simplify adding profile
support to those platforms in the future. This means `--profile` builds
will fail on Linux and Windows for now, but that's fine since they
aren't actually supported, and unlike `--release` don't provide useful
functionality at the native code level.

Also fixes 'stopApp' always using Debug on macOS, to avoid showing an
error when running Profile (or Release).

Fixes #33203

When building in profile or release mode on desktop, add a prominent
warning that it's actually a debug build. This is to help address issues
with people being unaware of the current state of builds due to
following third-party guides rather than official documentation.

macOS is not included since PRs are in flight for macOS release support.

This reverts commit bd52a78c.

Slight cleanup of file locations in flutter_tools
to make it easier to see which files are responsible
for data reporting.

- Adds desktop projects to ApplicationPackageStore
- Plumbs target overrides through the desktop builds

* Add emulatorId to Android and iOS emulator devices

* Update docs

* Review tweaks

* Add tests for AndroidConsole for getting avd names

* Remove unused import

* Remove duplicated header

* Fix imports

This reverts commit f221ad1f.

* Re-enable const