Aggregrate resource info properties for virtual views

[ishank011]

No description provided.

[C0rby]

What are virtual views? I'm currently rebasing #2016 and don't want to break this.

[ishank011]

@C0rby When listing / and let's say we have two providers mounted at /reva/users and /reva/projects, both should return /reva (after aggregrating the metrics of the underlying resources) and these should in turn be aggregrated in the gateway. Another use case which would need a lot of workarounds with #2016.

[butonic]

But that mixes concerns even further! The registry is responsible for the mount points. If no storage provider is mounted at / or at /reva then you cannot list those paths. Period. They don't exist. In https://github.com/cs3org/reva/pull/2023/files#diff-0d2961654453acb28ab32bc57e437cd52492efd9c76e2db3b49864e6322081a6R685 the gateway would learn how to calculate the etag for storage providers embedded via multiple path segments.

If you want to be able to navigate into /reva mount a storage provider with the eos driver that is configured to show the /reva dir.