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

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