Currently d.m.org struggles to start, as it is fetching several thousand
ACLs on startup.
The reason is that we're loading the entire room state into memory, only
to filter out the majority of it, because we only care about certain
types.
This change filters the types (tuples) directly when querying the
database, so we don't end up with unneeded state.
This now should actually speed up startup times.
This is because _many_ rooms (like DMs) don't have room ACLs, this means
that we had around 95% pointless DB queries. (as queried on d.m.org)
Since #3334 didn't change much on d.m.org, this is another attempt to
speed up startup.
Given moderation bots like Mjolnir/Draupnir are in many rooms with quite
often the same or similar ACLs, caching the compiled regexes _should_
reduce the startup time.
Using a pointer to the `*regexp.Regex` ensures we only store _one_
instance of a regex in memory, instead of potentially storing it hundred
of times. This should reduce memory consumption on servers with many
rooms with ACLs drastically. (5.1MB vs 1.7MB with this change on my
server with 8 ACL'd rooms [3 using the same ACLs])
[skip ci]
* Move currentstateserver API to roomserver
Stub out DB functions for now, nothing uses the roomserver version yet.
* Allow it to startup
* Implement some current-state-server storage interface functions
* Add missing package
