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/role.go

@@ -104,7 +104,7 @@ func (a *App) sendUpdatedRoleEvent(role *model.Role) {
 	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_ROLE_UPDATED, "", "", "", nil)
 	message.Add("role", role.ToJson())
 
-	a.Go(func() {
+	a.Srv.Go(func() {
 		a.Publish(message)
 	})
 }