Make versions available via PROPFIND requests #662

Is your feature request related to a problem? Please describe.

The web client would like to add a new feature to preview versions of a file without downloading or restoring them (see opencloud-eu/web#382). The way previews and editors work in web is by doing a PROPFIND on the file that is being opened. However, I can't manage to make this work for versions.

Describe the solution you'd like

I can request all versions for a file via a PROPFIND to remote.php/dav/meta/{fileId}/v. The response contains versions with a href prop like so: /remote.php/dav/meta/{fileId}/v/{versionId}. So I would expect to be able to make a PROPFIND to this endpoint.

Acceptance Criteria

• PROPFIND on versions works
• tests exist