Different features depending on Godot build

[RedMser]

My previous change fixed Default/Custom builds, but in turn broke Forked builds.

So now I've switched to conditional features and clarified this difference in documentation.

[RedMser]

Never mind it just seems like in one project, it tries loading FTL files on launch via ResourceFormatLoaderFluent. But in another project, it does not do that and starts up properly. Not sure why, but overall it makes sense that it crashes since background thread does scanning of file system in Godot.

Options:

• Maybe there is a way to defer / ignore invocations on main thread, instead of panic?
• Revert the feature changes on main branch :(

[RedMser]

Idea: disable registering the format loader when is editor hint is set to true? Might break adding ftl files to project settings in forked version, otherwise I'd hope it'd work.