Migrate to stateless app.App (#17542)

* add request context

* move initialialization to server

* use app interface instead of global app functions

* remove app context from webconn

* cleanup

* remove duplicated services

* move context to separate package

* remove finalize init method and move content to NewServer function

* restart workers and schedulers after adding license for tests

* reflect review comments

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/system_test.go

@@ -734,7 +734,7 @@ func TestServerBusy503(t *testing.T) {
 
 func TestPushNotificationAck(t *testing.T) {
 	th := Setup(t)
-	api := Init(th.Server, th.Server.AppOptions, th.Server.Router)
+	api := Init(th.App, th.Server.Router)
 	session, _ := th.App.GetSession(th.Client.AuthToken)
 	defer th.TearDown()
 	t.Run("should return error when the ack body is not passed", func(t *testing.T) {