Ristretto cache (#2563)

* 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

dendrite-sample.polylith.yaml

@@ -31,6 +31,25 @@ global:
   # considered valid by other homeservers.
   key_validity_period: 168h0m0s
 
+  # Configuration for in-memory caches. Caches can often improve performance by
+  # keeping frequently accessed items (like events, identifiers etc.) in memory
+  # rather than having to read them from the database.
+  cache:
+    # The estimated maximum size for the global cache in bytes, or in terabytes,
+    # gigabytes, megabytes or kilobytes when the appropriate 'tb', 'gb', 'mb' or
+    # 'kb' suffix is specified. Note that this is not a hard limit, nor is it a
+    # memory limit for the entire process. A cache that is too small may ultimately
+    # provide little or no benefit.
+    max_size_estimated: 1gb
+
+    # The maximum amount of time that a cache entry can live for in memory before
+    # it will be evicted and/or refreshed from the database. Lower values result in
+    # easier admission of new cache entries but may also increase database load in
+    # comparison to higher values, so adjust conservatively. Higher values may make
+    # it harder for new items to make it into the cache, e.g. if new rooms suddenly
+    # become popular.
+    max_age: 1h
+
   # The server name to delegate server-server communications to, with optional port
   # e.g. localhost:443
   well_known_server_name: ""