[GH-13058] Migrate webhookCache from store/sqlstore/webhook_st… (#13091)

* Migrate webhookCache from store/sqlstore/webhook_store.go to the new store/localcachelayer

* Remove duplicated statistics and move several functions to the layer

* Put cache size in format minutes * 60seconds

* Move cache functions to layer functions over the caches

* Directly remove and purge caches in handleClusterInvalidate to avoid loops

model/cluster_message.go

@@ -24,6 +24,7 @@ const (
 	CLUSTER_EVENT_CLEAR_SESSION_CACHE_FOR_USER                      = "clear_session_user"
 	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_ROLES                        = "inv_roles"
 	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_SCHEMES                      = "inv_schemes"
+	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_WEBHOOKS                     = "inv_webhooks"
 	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_EMOJIS_BY_ID                 = "inv_emojis_by_id"
 	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_EMOJIS_ID_BY_NAME            = "inv_emojis_id_by_name"
 	CLUSTER_EVENT_INVALIDATE_CACHE_FOR_CHANNEL_MEMBER_COUNTS        = "inv_channel_member_counts"