Add common Disposable API

[tortmayr]

Provide a reusable Disposable API similar to what Theia/VS Code uses
Part of eclipse-glsp/glsp#867

Also: Update dev packages and autoformat package.json files

[martin-fleck-at]

API looks good to me in general, thank you very much Tobias! If we ever need more functionality (e.g., listeners) we can always add them later. I was only wondering on whether we should already use the API in this package, e.g., there are a few places where we have register/deregister methods (e.g., tools, listeners, etc.) where the register call could return the corresponding deregister instead of void. Or will there be a separate task/PR for that?

[tortmayr]

If we ever need more functionality (e.g., listeners) we can always add them later. I was only wondering on whether we should already use the API in this package, e.g., there are a few places where we have register/deregister methods (e.g., tools, listeners, etc.) where the register call could return the corresponding deregister instead of void. Or will there be a separate task/PR for that?

I think we should do that in a separate PR.

[martin-fleck-at]

LGTM!