Follow-up to https://github.com/flutter/flutter/pull/143347.
As https://github.com/flutter/flutter/pull/143403 uncovered, deprecation warnings were still enabled for the mega_gallery because it doesn't use the analysis_options.yaml file from the flutter root. This change injects a analysis_options.yaml file for the mega_gallery that disables those warnings.
Submitting this separately from https://github.com/flutter/flutter/pull/143403 in case it affects the mega_gallery benchmark to get a clean new baseline before removing all the `deprecated_member_use` ignores.
Move Flutter Gallery to dev/integration_tests/ as it is an older copy used only for testing. The current version of the Flutter Gallery now lives in https://github.com/flutter/gallery.
* 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
* Enable lint unnecessary_statements. Codebase is compliant.
* Fix mega_gallery generated code to not generate unecessary statements
* Fix lint in mega gallery changes
* Enable unnecessary_statements for users as well as repo.
