* commit 'adfdd82b2':
Back out perf regression from get_cross_signing_keys_from_cache. (#6494)
Fix comment
Fix port db script
Newsfile
Fixup tests
Move start up DB checks to main data store.
Pass Database into the data store
Move are_all_users_on_domain checks to main data store.
Change DataStores to accept 'database' param.
Implements MSC2290. This PR adds two new endpoints, /unstable/account/3pid/add and /unstable/account/3pid/bind. Depending on the progress of that MSC the unstable prefix may go away.
This PR also removes the blacklist on some 3PID tests which occurs in #6042, as the corresponding Sytest PR changes them to use the new endpoints.
Finally, it also modifies the account deactivation code such that it doesn't just try to deactivate 3PIDs that were bound to the user's account, but any 3PIDs that were bound through the homeserver on that user's account.
