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/channel_category_test.go

@@ -438,7 +438,7 @@ func TestUpdateCategoriesForTeamForUser(t *testing.T) {
 
 func setupUserForSubtest(t *testing.T, th *TestHelper) (*model.User, *model.Client4) {
 	password := "password"
-	user, err := th.App.CreateUser(&model.User{
+	user, err := th.App.CreateUser(th.Context, &model.User{
 		Email:    th.GenerateTestEmail(),
 		Username: "user_" + model.NewId(),
 		Password: password,