Added post limit warning (#26793)

* Renamed user limit API to app limit API

* Added post warning limit

* Added tests

* Fixed types

* Renamed AppLimits to ServerLimits

* Fixed tests and review fixes

* Updated generated code

* Updated server i18n

* Fixed TestCreateUserOrGuest test

* Exclude deleted posts from post count for liims

* Reduced limits for ease of testing

* Restored original limts

api/v4/source/definitions.yaml

@@ -3637,7 +3637,7 @@ components:
         state:
           description: The current state of the installation
           type: string
-    UserLimits:
+    ServerLimits:
       type: object
       properties:
         maxUsersLimit: