Don't require config to create database

Move _get_cache_dict into the SQLBaseStore

Make the cache objects be per instance rather than being global

Separate generating the replication response...

Don't backfill from self

Fix stuck invites

from doing the http request parsing to make it easier
to write unit tests for replication.

If rejecting a remote invite fails with an error response don't fail
the entire request; instead mark the invite as locally rejected.

This fixes the bug where users can get stuck invites which they can
neither accept nor reject.

Store invites in a separate table.

Do checks for memberships before creating events

Use google style doc strings.

pycharm supports them so there is no need to use the other format.

Might as well convert the existing strings to reduce the risk of
people accidentally cargo culting the wrong doc string format.

Use a stream id generator for backfilled ids

Add concurrently_execute function

Fix the invalidation of the names and aliases cache

Remove outlier parameter from compute_event_context

Use event.internal_metadata.is_outlier instead.

Remove the is_new_state argument to persist event.

Move the checks for whether an event is new state inside persist
event itself.

This was harder than expected because there wasn't enough information
passed to persist event to correctly handle invites from remote servers
for new rooms.

Split out RoomMemberHandler