Return free disk space if quota is set to unlimited

[KopfKrieg]

Currently, if there's no quota set (alias "unlimited"), users don't know how much free space is available on the server.

It would be nice, if nextcloud would return the free space if the quota is set to unlimited. Currently, this can be simulated by setting the quota > disk space.

[MorrisJobke]

The propfind will always return the quota type like this:

<d:quota-available-bytes>-3</d:quota-available-bytes>

But if you query the users API https://HOST/ocs/v1.php/cloud/user for example you will get the remaining bytes:

<?xml version="1.0"?>
<ocs>
	<meta>
		<status>ok</status>
		<statuscode>100</statuscode>
		<message>OK</message>
		<totalitems></totalitems>
		<itemsperpage></itemsperpage>
	</meta>
	<data>
		<enabled>true</enabled>
		<id>admin</id>
		<quota>
			<free>145686192128</free>
			<used>164</used>
			<total>145686192292</total>
			<relative>0</relative>
			<quota>-3</quota>
		</quota>
		<email/>
		<phone></phone>
		<address></address>
		<website></website>
		<twitter></twitter>
		<groups>
			<element>admin</element>
		</groups>
		<language>en</language>
		<display-name>admin</display-name>
	</data>
</ocs>

@icewind1991 @rullzer would it make sense to add this to the PROPFIND as well?