RBAC: Optimize permissions caching (#92673)

* Access control: Use composite cache key for team permissions

* use composite key for teams

* use cache for hotpath (getCachedUserPermissions)

* don't cache empty teams set

* don't pass permissions as argument

* early return if no teams found

* reload cache correctly

* optimize allocations

* Clear user's teams cache

* remove composite cache for teams

* fix linter

* don't clear teams permissions

* pre-allocate memory for basic roles permissions

pkg/services/accesscontrol/cacheutils.go

@@ -7,7 +7,7 @@ import (
 	"github.com/grafana/grafana/pkg/apimachinery/identity"
 )
 
-func GetPermissionCacheKey(user identity.Requester) string {
+func GetUserPermissionCacheKey(user identity.Requester) string {
 	return fmt.Sprintf("rbac-permissions-%s", user.GetCacheKey())
 }