feat(cache): redis cache (#8822)

# Which Problems Are Solved

Add a cache implementation using Redis single mode. This does not add
support for Redis Cluster or sentinel.

# How the Problems Are Solved

Added the `internal/cache/redis` package. All operations occur
atomically, including setting of secondary indexes, using LUA scripts
where needed.

The [`miniredis`](https://github.com/alicebob/miniredis) package is used
to run unit tests.

# Additional Changes

- Move connector code to `internal/cache/connector/...` and remove
duplicate code from `query` and `command` packages.
- Fix a missed invalidation on the restrictions projection

# Additional Context

Closes #8130

internal/cache/connector/pg/prune.sql

@@ -0,0 +1,18 @@
+delete from cache.objects o
+where o.cache_name = $1
+	and (
+		case when $2::interval > '0s'
+			then created_at < now()-$2::interval -- max age
+			else false
+		end
+		or case when $3::interval > '0s'
+			then last_used_at < now()-$3::interval -- last use
+			else false
+		end
+		or o.id not in (
+			select object_id
+			from cache.string_keys
+			where cache_name = $1
+		)
+	)
+;