Fix federation for #test:matrix.org

... rather than rejecting any attempt to federate channels which contain such
events.

Fix adding push rules relative to other rules

This is for setting up dependencies that require work on startup. This
is useful for the DataStore that wants to read a bunch from the database
before initiliazing.

Only notify for messages in one to one rooms, not every event

Fixes the fact that candidate events and hangups generated notifications.

Add missing yield in push_rules set enabled

Move some sync logic from rest to handlers pacakege

Implement a `_simple_select_many_batch`

Push: Use storage apis that are cached

Add index to event_push_actions

Underscores are allowed in user ids

Better fix for actions with both dont_notify and tweaks

Don't add notifications to the table unless there's actually a 'notify' action

Overlay the push_rules_enabled map for users

Overlay the push_rules_enabled map for users, otherwise they won't be able to disable server default rules.

Make LRU caching tree-based so subtrees of the cache can be invalidated cheaply.