It was removed, but it needs to get back (the whole frontend application) in order to allow user login. This is a necessary step for granting OAuth token to external applications.
So:
login/logout need to work again
/oauth/authorize should redirect to /login when necessary
We used to have the ability to login: https://github.com/adsabs/adsws/tree/dddaabe413a31f1ceb4652e99d1cb908f518611e/adsws/frontend
It was removed, but it needs to get back (the whole frontend application) in order to allow user login. This is a necessary step for granting OAuth token to external applications.
So: