Reduce webrtc dependency to a single one

[thomaseizinger]

Description

Depending on the recent webrtc master branch breaks a couple of things because of the move to the monorepo I assume. To ensure CI stability of our dev branch, we pin the dependency to a specific hash. At the same time, depending on the various subcrates may result in mismatching versions. To avoid this, we remove those dependencies and import the modules via the re-export from the root webrtc crate.

Links to any relevant issues

Open Questions

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[thomaseizinger]

I can't request a review but would appreciate one from @melekes and @mxinden!

[melekes]

👍

[thomaseizinger]

Feel free to merge at any time @melekes! (I can't.)