Federated starring is very similar to federated following but requires the database to store remote repos in some way. It uses the ActivityPub `Like` activity and the `liked` collection.

We also need to implement ForgeFed ourselves since it is not included in go-ap.

### TODO

- [ ] Handle remote repos in the database
- [X] Create actor endpoint for repos (similar to what we have right now for users)
- [X] API endpoints for returning `liked` collection
- [ ] Implement function for fetching `liked` items and returing a collection
- [ ] Function for handling `Like` activities for the inbox