[MM-42739] Insights - Top Channels API Endpoint (#19953)

* [MM-42739] Initial setup for top channels for team

* [MM-42739] Add initial tests

* [MM-42739] Update tests

* [MM-42739] Add top channels for user

* [MM-42739] Fix query

* [MM-42739] Update query

* [MM-42739] Improve query performance

* [MM-42739] Remove rank

* [MM-42739] Fix tests to use new time range today

* [MM-42739] Add tests for top channels for user

* [MM-42739] Add test for pagination

* Remove top channels by time struct

* [MM-42739] Update test names

* [MM-42739] Remove rank from top reactions

* [MM-42739] Return empty array instead of nil when result is empty

* [MM-42739] Add additional tests and update permissions check for teams

* [MM-42739] Add excluded channel tests for top reactions

* [MM-42739] Move insights to api4/insights and keep time range as string until required

* [MM-42739] Update queries only check DeleteAt after union

* [MM-42739] Improve query performance by using publicchannels table

* [MM-42739] Fix broken query after merge

api4/api.go

@@ -134,6 +134,9 @@ type Routes struct {
 	SharedChannels *mux.Router // 'api/v4/sharedchannels'
 
 	Permissions *mux.Router // 'api/v4/permissions'
+
+	InsightsForTeam *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9]+}/top'
+	InsightsForUser *mux.Router // 'api/v4/users/me/top'
 }
 
 type API struct {
@@ -255,6 +258,9 @@ func Init(srv *app.Server) (*API, error) {
 
 	api.BaseRoutes.Permissions = api.BaseRoutes.APIRoot.PathPrefix("/permissions").Subrouter()
 
+	api.BaseRoutes.InsightsForTeam = api.BaseRoutes.Team.PathPrefix("/top").Subrouter()
+	api.BaseRoutes.InsightsForUser = api.BaseRoutes.Users.PathPrefix("/me/top").Subrouter()
+
 	api.InitUser()
 	api.InitBot()
 	api.InitTeam()
@@ -296,6 +302,7 @@ func Init(srv *app.Server) (*API, error) {
 	api.InitSharedChannels()
 	api.InitPermissions()
 	api.InitExport()
+	api.InitInsights()
 	if err := api.InitGraphQL(); err != nil {
 		return nil, err
 	}