feat(storage): generic cache interface (#8628)

# Which Problems Are Solved

We identified the need of caching.
Currently we have a number of places where we use different ways of
caching, like go maps or LRU.
We might also want shared chaches in the future, like Redis-based or in
special SQL tables.

# How the Problems Are Solved

Define a generic Cache interface which allows different implementations.

- A noop implementation is provided and enabled as.
- An implementation using go maps is provided
  - disabled in defaults.yaml
  - enabled in integration tests
- Authz middleware instance objects are cached using the interface.

# Additional Changes

- Enabled integration test command raceflag
- Fix a race condition in the limits integration test client
- Fix a number of flaky integration tests. (Because zitadel is super
fast now!) 🎸 🚀

# Additional Context

Related to https://github.com/zitadel/zitadel/issues/8648

internal/api/grpc/admin/import.go

@@ -123,7 +123,9 @@ func (s *Server) ImportData(ctx context.Context, req *admin_pb.ImportDataRequest
 			return nil, ctxTimeout.Err()
 		case result := <-ch:
 			logging.OnError(result.err).Errorf("error while importing: %v", result.err)
-			logging.Infof("Import done: %s", result.count.getProgress())
+			if result.count != nil {
+				logging.Infof("Import done: %s", result.count.getProgress())
+			}
 			return result.ret, result.err
 		}
 	} else {