perf(cache): pgx pool connector (#8703)

# Which Problems Are Solved

Cache implementation using a PGX connection pool.

# How the Problems Are Solved

Defines a new schema `cache` in the zitadel database.
A table for string keys and a table for objects is defined.
For postgreSQL, tables are unlogged and partitioned by cache name for
performance.

Cockroach does not have unlogged tables and partitioning is an
enterprise feature that uses alternative syntax combined with sharding.
Regular tables are used here.

# Additional Changes

- `postgres.Config` can return a pxg pool. See following discussion

# Additional Context

- Part of https://github.com/zitadel/zitadel/issues/8648
- Closes https://github.com/zitadel/zitadel/issues/8647

---------

Co-authored-by: Silvan <silvan.reusser@gmail.com>

internal/cache/cache.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/zitadel/logging"
+	"github.com/zitadel/zitadel/internal/database/postgres"
 )
 
 // Cache stores objects with a value of type `V`.
@@ -55,9 +56,6 @@ type Cache[I, K comparable, V Entry[I, K]] interface {
 
 	// Truncate deletes all cached objects.
 	Truncate(ctx context.Context) error
-
-	// Close the cache. Subsequent calls to the cache are not allowed.
-	Close(ctx context.Context) error
 }
 
 // Entry contains a value of type `V` to be cached.
@@ -75,8 +73,8 @@ type Entry[I, K comparable] interface {
 
 type CachesConfig struct {
 	Connectors struct {
-		Memory MemoryConnectorConfig
-		// SQL database.Config
+		Memory   MemoryConnectorConfig
+		Postgres PostgresConnectorConfig
 		// Redis redis.Config?
 	}
 	Instance *CacheConfig
@@ -104,3 +102,9 @@ type MemoryConnectorConfig struct {
 	Enabled   bool
 	AutoPrune AutoPruneConfig
 }
+
+type PostgresConnectorConfig struct {
+	Enabled    bool
+	AutoPrune  AutoPruneConfig
+	Connection postgres.Config
+}