Replace getstoragestats.php by PROPFIND on current folder

[PVince81]

The FileList object already had a dirInfo object containing the PROPFIND result on the current directory. From here we can already extra information like remaining quota.

Here are the different values from getstoragestats which we should get rid of / move to somewhere else:

• max_upload => move to capabilities API Expose PHP max upload size through capabilities API #26068 💀 Remove upload_limit in files app as it is not needed with PUT upload #26069
• free_space => use fileList.dirInfo instead (quota-available-bytes)
• max_human_file_size => 💀
• usedSpacePercent => use fileList.dirInfo (quota-used-bytes) instead
• owner => use fileList.dirInfo owner instead
• ownerDisplayName => use fileList.dirInfo owner display name instead

[PVince81]

• low space warnings: Maybe we need a PROPFIND on the home/root folder to get accurate used space for the low space warnings
• setInterval: still needed ? if yes, move this to the filelist. A regular PROPFIND on the current folder (or root) with If-Match of last etag, to detect changes. Not sure if used space changes are covered.

[PVince81]

Ok, turns out that "owner" and "ownerDiplsayName" and "usedSpacePercent" are all used by the warning, so using the value from the current folder should be enough.

[PVince81]

PR here: #26070

[PVince81]

Maybe we should get rid of polling this altogether (see related #26077). This means that any file upload will always go through with PUT and the server will tell if there is not enough space currently.

In the past when using POST, an upload was expensive and would only ever reach the OC code at the end of the upload. Here with PUT we have a chance to check the free space early before even reading the payload.

[PVince81]

Not finishable because we'd lose the "storage warnings" notifications.
So need to wait for https://github.com/owncloud/core/issues/6878 to have these warnings be real notifications.