HW 4139: Make channel limits configurable in the System Console (#4154)

* Auto Changes

* 4139 Made channel limits configurable in the System Console as described in the issue

* Removed error message entries from other locales, made maxChannelsPerteam type to pointer

* Added * symbol to maxChannelsPerTeam inside isValid function

* Update team_test.go

* Restored to old test

* Checked maximum number channels per team when creating channel

* Fixed code to pass api/channel_test.go

* Reverted changes on config except MaxChannelsPerTeam

* Update channel.go

* Ran gofmt -w .

* Reverted vendor directoy

config/config.json

@@ -51,7 +51,8 @@
         "RestrictTeamInvite": "all",
         "RestrictPublicChannelManagement": "all",
         "RestrictPrivateChannelManagement": "all",
-        "UserStatusAwayTimeout": 300
+        "UserStatusAwayTimeout": 300,
+        "MaxChannelsPerTeam": 2000
     },
     "SqlSettings": {
         "DriverName": "mysql",