Team/Channel members bulk save/update/delete (#14053)

* Members Save Multiple

* Multiple Channel Members implemented

* Working version with member multi save and multi update

* Adding tests to the save multiple team members store methods

* Tests passing for SaveMember

* Adding remove members tests

* Working on channel store tests

* More work on testing properly SaveMember and SaveMultipleMembers on channels

* More work on testing properly SaveMember and SaveMultipleMembers on teams

* Adding tests for update multiple members for team

* Adding tests for update multiple members for channel

* Fixing some tets

* Fixing tests

* Fixing tests

* Fixing i18n

* Addressing govet problems

* Addressing govet problems

* Addressing govet problems

* Addressing govet problems

* Addressing PR comments (and removing TODO)

* Addressing PR comments

* Fixed broken test

* Removing unnecesary i18n translation string

store/sqlstore/team_store_test.go

@@ -150,7 +150,7 @@ func testTeamMemberWithSchemeRolesToModel(t *testing.T) {
 
 		m := db.ToModel()
 
-		assert.Equal(t, "team_user custom_role", m.Roles)
+		assert.Equal(t, "custom_role team_user", m.Roles)
 		assert.Equal(t, false, m.SchemeGuest)
 		assert.Equal(t, true, m.SchemeUser)
 		assert.Equal(t, false, m.SchemeAdmin)
@@ -170,7 +170,7 @@ func testTeamMemberWithSchemeRolesToModel(t *testing.T) {
 
 		m := db.ToModel()
 
-		assert.Equal(t, "team_user team_admin custom_role", m.Roles)
+		assert.Equal(t, "custom_role team_user team_admin", m.Roles)
 		assert.Equal(t, false, m.SchemeGuest)
 		assert.Equal(t, true, m.SchemeUser)
 		assert.Equal(t, true, m.SchemeAdmin)