Migrate functions to app package (#5106)

* Refactor and move session logic into app package

* Refactor email functions into the app package

* Refactor password update into app package

* Migrate user functions to app package

* Move team functions into app package

* Migrate channel functions into app package

* Pass SiteURL through to app functions

* Update based on feedback

web/web_test.go

@@ -209,7 +209,7 @@ func TestIncomingWebhook(t *testing.T) {
 	store.Must(app.Srv.Store.User().VerifyEmail(user.Id))
 	app.JoinUserToTeam(team, user)
 
-	api.UpdateUserRoles(user, model.ROLE_SYSTEM_ADMIN.Id)
+	app.UpdateUserRoles(user.Id, model.ROLE_SYSTEM_ADMIN.Id)
 	ApiClient.Login(user.Email, "passwd1")
 	ApiClient.SetTeamId(team.Id)