This removes most of the code used for polylith/API mode.
This removes the `/api` internal endpoints entirely.
Binary size change roughly 5%:
```
51437560 Feb 13 10:15 dendrite-monolith-server # old
48759008 Feb 13 10:15 dendrite-monolith-server # new
```
* Try Ristretto cache
* Tweak
* It's beautiful
* Update GMSL
* More strict keyable interface
* Fix that some more
* Make less panicky
* Don't enforce mutability checks for now
* Determine mutability using deep equality
* Tweaks
* Namespace keys
* Make federation caches mutable
* Update cost estimation, add metric
* Update GMSL
* Estimate cost for metrics better
* Reduce counters a bit
* Try caching events
* Some guards
* Try again
* Try this
* Use separate caches for hopefully better hash distribution
* Fix bug with admitting events into cache
* Try to fix bugs
* Check nil
* Try that again
* Preserve order jeezo this is messy
* thanks VS Code for doing exactly the wrong thing
* Try this again
* Be more specific
* aaaaargh
* One more time
* That might be better
* Stronger sorting
* Cache expiries, async publishing of EDUs
* Put it back
* Use a shared cache again
* Cost estimation fixes
* Update ristretto
* Reduce counters a bit
* Clean up a bit
* Update GMSL
* 1GB
* Configurable cache sizees
* Tweaks
* Add `config.DataUnit` for specifying friendly cache sizes
* Various tweaks
* Update GMSL
* Add back some lazy loading caching
* Include key in cost
* Include key in cost
* Tweak max age handling, config key name
* Only register prometheus metrics if requested
* Review comments @S7evinK
* Don't return errors when creating caches (it is better just to crash since otherwise we'll `nil`-pointer exception everywhere)
* Review comments
* Update sample configs
* Update GHA Workflow
* Update Complement images to Go 1.18
* Remove the cache test from the federation API as we no longer guarantee immediate cache admission
* Don't check the caches in the renewal test
* Possibly fix the upgrade tests
* Update to matrix-org/gomatrixserverlib#322
* Update documentation to refer to Go 1.18
* Look up servers less often, don't hit API for missing auth events unless there are actually missing auth events
* Remove ResolveConflictsAdhoc (since it is already in GMSL), other tweaks
* Update gomatrixserverlib to matrix-org/gomatrixserverlib#254
* Fix resolve-state
* Initialise t.servers on first use
* Add resolve-state helper
* Tweaks
* Refactor forward extremities, again
* Tweaks
* Minor optimisation
* Make path a bit clearer
* Only process state/membership if forward extremities have changed
* Usage comments in resolve-state
