This adds iOS key map generation that uses std::maps. It uses std::maps because on iOS if we use NSDictionaries, then when XCode loads the dylib, the initialization of those status NSDictionaries hasn't yet occurred, and it crashes the app. std::maps have a well-defined static behavior, and are correctly initialized.

I also made the naming of variables, fields, etc. consistent for macOS. We variously had macosFoo, macOSFoo, and macOsFoo. I eliminated macOsFoo and macosFoo, since the rest of the repo uses macOSFoo for lowerCamelCase names (with only a few exceptions). I used iOSFoo for iOS.

* Migrate flutter conductor out of dev/tools and into its own directory

* flesh out documentation

* fix analysis options

* fix integration test

* Make RouteInformationProvider value non nullable

* fix more lint

2576d6b8b [camera] android-rework part 4: Android flash and zoom features (flutter/plugins#3798) (#83364)

This is bassically reapplying #71721, but only enables it on web tests.

There are known issues that several tests under the `integration.shard`
depend on a specific platform, and as a result they require some
additional flexiblity (bots need to build more than one engine, and the
test flags should allow for secondary engines to be picked by such
tests).

By enabling this on the web-test shard, we will reduce the false
positives in the dart-flutter-HHH-web bot.

Fixing the more general problem is tracked by #72368.