refactor(parser)!: Implement endpoint/command parsers

[LuanRT]

Closes #810

The old request builders (under the Endpoints namespace) have been removed. Those who relied on them should now use the NavigationEndpoint node to build requests.

Example:

const continuationCommand = new YTNodes.NavigationEndpoint({
    continuationCommand: {
        request: 'CONTINUATION_REQUEST_TYPE_WATCH_NEXT',
        token: continuation
    }
});

const response = await continuationCommand.call(innertube.session.actions, /** additional payloads, etc */);
console.log(response);

Why?

The old request builders were messy and incompatible with the parser. With this PR, the parser can correctly identify endpoints, commands, and build request payloads.

[absidue]

Before this gets merged, I would like to try adding support for this gigantic refractoring in FreeTube, we definitely need to make changes on our side. I want to check that FreeTube can still do everything that it currently does, so that I can request changes if necessary before this is merged.

[LuanRT]

^^ Technically, this is also a breaking change. This was going to be a big refactor anyway, so I went ahead fixed some typos and removed deprecated code (like the YouTube Studio stuff).

[absidue]

As this will trigger a major version bump because of the breaking changes, should we also use it as an opportunity to get rid of some of the dead nodes?

In a separate pull request of course (wouldn't want to make this one even bigger) but in the same release because it will also be a breaking change (TypeScript users will probably get type errors after the dead nodes are removed).

[absidue]

Less changes were necessary to FreeTube than expected (just 3 minor ones). I did notice that this increases FreeTube's bundle size by 15 kb compared to the main branch, which is likely because the endpoints used to be just variables and functions that could be inlined and now they are fully fledged classes, it's not a big deal though.