Add force_login option to OAuth authorize page (#8655)

* Add force_login option to OAuth authorize page

For when a user needs to sign into an app from multiple accounts
on the same server

* When logging out from modal header, redirect back after re-login

spec/controllers/auth/sessions_controller_spec.rb

@@ -30,6 +30,13 @@ RSpec.describe Auth::SessionsController, type: :controller do
 
         expect(response).to redirect_to(new_user_session_path)
       end
+
+      it 'does not delete redirect location with continue=true' do
+        sign_in(user, scope: :user)
+        controller.store_location_for(:user, '/authorize')
+        delete :destroy, params: { continue: 'true' }
+        expect(controller.stored_location_for(:user)).to eq '/authorize'
+      end
     end
 
     context 'with a suspended user' do