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.

I noticed that tab traversal stopped working on iOS when #73440 was landed.

It seems to be that the control characters were excluded from the list of logical keys, and so they ended up being generated values.

This PR just adds "Enter" and "Tab" to the list for both macOS and iOS.

Removes webValues from logical_key_data.json. Web's logical mapping should map webNames to logical key values, i.e. entry.value.

Rewrites tools/gen_keycodes, the script that generates key mappings across the framework and the engine.