[MM-38216] Add API endpoint and adapt search to allow multi-team search (#18371)

* Add API endpoint and adapt search to allow multi-team search

* Refactor handler, refactor sql query to use squirrel, rename app and store functions and add tests

* Fix lint

* Fix search engines and remove unneeded comments

* Fix test

* Remove user from channel after test

store/timerlayer/timerlayer.go

@@ -5193,10 +5193,10 @@ func (s *TimerLayerPostStore) Search(teamID string, userID string, params *model
 	return result, err
 }
 
-func (s *TimerLayerPostStore) SearchPostsInTeamForUser(paramsList []*model.SearchParams, userID string, teamID string, page int, perPage int) (*model.PostSearchResults, error) {
+func (s *TimerLayerPostStore) SearchPostsForUser(paramsList []*model.SearchParams, userID string, teamID string, page int, perPage int) (*model.PostSearchResults, error) {
 	start := timemodule.Now()
 
-	result, err := s.PostStore.SearchPostsInTeamForUser(paramsList, userID, teamID, page, perPage)
+	result, err := s.PostStore.SearchPostsForUser(paramsList, userID, teamID, page, perPage)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {
@@ -5204,7 +5204,7 @@ func (s *TimerLayerPostStore) SearchPostsInTeamForUser(paramsList []*model.Searc
 		if err == nil {
 			success = "true"
 		}
-		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.SearchPostsInTeamForUser", success, elapsed)
+		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.SearchPostsForUser", success, elapsed)
 	}
 	return result, err
 }