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

server/public/model/limits.go

@@ -3,8 +3,11 @@
 
 package model
 
-type UserLimits struct {
+type ServerLimits struct {
 	MaxUsersLimit     int64 `json:"maxUsersLimit"`     // soft limit for max number of users.
 	MaxUsersHardLimit int64 `json:"maxUsersHardLimit"` // hard limit for max number of active users.
 	ActiveUserCount   int64 `json:"activeUserCount"`   // actual number of active users on server. Active = non deleted
+
+	MaxPostLimit int64 `json:"maxPostLimit"` // soft limit for max number of posts
+	PostCount    int64 `json:"postCount"`    // actual number of posts in system.
 }