Add SUPPORTS_LOCAL_API build flag

[absidue]

Add SUPPORTS_LOCAL_API build flag

Pull Request Type

• Build improvement

Description

This pull request adds a new build flag SUPPORTS_LOCAL_API. Now that the local API no longer requires Electron specific functionality (e.g. reading and writing to the file system), it makes sense to place the local API behind a different build flag, this will reduce the maintaince burden on @MarmadileManteater for FreeTubeAndroid. This also has no impact on the Electron build, yes I checked the renderer.js file kept the same size that it had before this pull request (the UniversalCache class gets correctly treeshaken out).

Note for users that might see this pull request and get the wrong idea...

Important

This does not add support for the local API anywhere where it wasn't already supported before (Electron and the Android build in FreeTubeAndroid). Only set this flag to true if you know that the local API will actually run in the target environment, that means CORS bypasses and other things have to be in-place.

Testing

Electron

Check that the local API still works (you don't need to check everywhere, if it works in a few places, the rest should work too, as I copy pasted the name to avoid typos)

Web

1. yarn run dev:web
2. Check that the only option for the preferred backend setting is Invidious

Desktop

• OS: Windows
• OS Version: 10
• FreeTube version: 0.20.0