Remove the internal API

* Bind sessions to identities
* Remove references to the identity token
* Move email changes to identity
* Move account menu into a turbo-frame
* Create tenants from a tenanted route

test/controllers/controller_authentication_test.rb

@@ -1,13 +1,13 @@
 require "test_helper"
 
 class ControllerAuthenticationTest < ActionDispatch::IntegrationTest
-  test "access without an account slug redirects to login menu" do
-    identify_as :kevin
+  test "access without an account slug redirects to menu" do
+    sign_in_as :kevin
     integration_session.default_url_options[:script_name] = "" # no tenant
 
     get cards_path
 
-    assert_redirected_to session_login_menu_path
+    assert_redirected_to session_menu_path
   end
 
   test "access with an account slug but no session redirects to new session" do