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whatever build failure the breaking change causes and having to figure out that the problem is that the runner is out of date.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
* 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
When we were running `pub` within `flutter pub`, we were
unconditionally including the `--verbosity=warning` argument.
Then we were conditionally including `--verbose` if we were
running in verbose mode. However, the former argument
supersedes the latter, and we were never able to run `pub`
in verbose mode.
* add trailing commas on list/map/parameters
* add trailing commas on Invocation with nb of arg>1
* add commas for widget containing widgets
* add trailing commas if instantiation contains trailing comma
* revert bad change
