WIP: apptokens

[jessegeens]

Config is available in the puppet dev environment

How to test

1. Point the NextCloud Desktop client at https://<box>:9998.
2. The client will POST /index.php/login/v2 → receives poll-token + login URL.
3. It opens the login URL in a browser: GET /index.php/login/v2/flow/ → the server auto-approves and shows "Access granted".
4. The client's next poll returns {loginName: "jgeens", appPassword: "..."}.
5. From then on, WebDAV/OCS calls use Basic-Auth with those credentials, verified via the existing appauth auth manager chai

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.