Move hover provider registry to the web worker
Created by: twop
done:
- moved hover registry and all corresponding logic to the webworker
not done:
- lifetime of hover registry. The way it worked that registry was always available and reissued hover queries once we have a registered provider. Now though, it is not possible to issue a hover query before worker is initialized.
- fix tests
- add tests
- general cleanup.
Please treat this PR as an early wip to validate the direction (for hover registry and all others)