Guest accounts feature (#11428)

* MM-14139: Creating permissions for invite/promote/demote guests (#10778)

* MM-14139: Creating permissions for invite/promote/demote guests

* Fixing tests

* Adding invite guest api endpoint (#10792)

* Adding invite guest api endpoint

* Adding i18n

* Adding some tests

* WIP

* Migrating Token.Extra info to bigger size (2048)

* Fixing tests

* Adding client function for invite guests

* Adding send guests invites tests

* Renaming file from guest to guest_invite

* Adding Promote/Demote users from/to guest endpoints (#10791)

* Adding Promote/Demote users from/to guest endpoints

* Adding i18n translations

* Adding the client functions

* Using getQueryBuilder function

* Addressing PR review comments

* Adding default channels to users on promte from guest (#10851)

* Adding default channels to users on promte from guest

* Addressing PR review comments

* Fixing merge problems

* Sending websockets events on promote/demote (#11403)

* Sending websockets events on promote/demote

* Fixing merge problems

* Fixing govet shadowing problem

* Fixing feature branch tests

* Avoiding leaking users data through websockets for guest accounts (#11489)

* Avoiding leaking users data through websockets for guest accounts

* Adding tests and fixing code error

* Fixing i18n

* Allow to enable/disable guests and other extra config settings (#11481)

* Allow to enable/disable guests and other extra config settings

* Fixing tests and moving license and config validation to api level

* Update api4/role_test.go

Co-Authored-By: George Goldberg <george@gberg.me>

* Update api4/role_test.go

Co-Authored-By: George Goldberg <george@gberg.me>

* Fixing typo

* fixing tests

* Managing correctly the guest channel leave behavior (#11578)

* MM-15134: Removing guests from teams or system on leave channels if needed

* WIP

* No deactivating the guest user when leave the last team

* Adding a couple of tests

* Fixing shadow variables

* Fixing tests

* fixing tests

* fixing shadow variables

* Adding guest counts for channel stats (#11646)

* Adding guest counts for channel stats

* Adding tests

* Fixing tests

* Fixing guest domain restrictions (#11660)

* Adding needed migration for the database

* Fixing migration

model/session.go

@@ -22,6 +22,7 @@ const (
 	SESSION_PROP_IS_BOT               = "is_bot"
 	SESSION_PROP_IS_BOT_VALUE         = "true"
 	SESSION_TYPE_USER_ACCESS_TOKEN    = "UserAccessToken"
+	SESSION_PROP_IS_GUEST             = "is_guest"
 	SESSION_ACTIVITY_TIMEOUT          = 1000 * 60 * 5 // 5 minutes
 	SESSION_USER_ACCESS_TOKEN_EXPIRY  = 100 * 365     // 100 years
 )