MM-12849 Moving all non request scoped items to Server struct (#9806)

* Moving goroutine pool

* Auto refactor

* Moving plugins.

* Auto refactor

* Moving fields to server

* Auto refactor

* Removing siteurl duplication.

* Moving reset of app fields

* Auto refactor

* Formatting

* Moving niling of Server to after last use

* Fixing unit tests.

app/scheme.go

@@ -152,7 +152,7 @@ func (a *App) GetChannelsForScheme(scheme *model.Scheme, offset int, limit int)
 }
 
 func (a *App) IsPhase2MigrationCompleted() *model.AppError {
-	if a.phase2PermissionsMigrationComplete {
+	if a.Srv.phase2PermissionsMigrationComplete {
 		return nil
 	}
 
@@ -160,7 +160,7 @@ func (a *App) IsPhase2MigrationCompleted() *model.AppError {
 		return model.NewAppError("App.IsPhase2MigrationCompleted", "app.schemes.is_phase_2_migration_completed.not_completed.app_error", nil, result.Err.Error(), http.StatusNotImplemented)
 	}
 
-	a.phase2PermissionsMigrationComplete = true
+	a.Srv.phase2PermissionsMigrationComplete = true
 
 	return nil
 }