Refactor member providers

[gnunicorn]

Profiles are room specific, so at the very least we need roomid and user ID. But then, because this is called from so many different places, if we wouldn't get the already loaded objects, we'd have to load them ourselves and as there are different providers used in all these circumstances we wouldn't reuse the cached data but instead potentially load it all from the API again, bring potentially a lot slower.

We do now have a rooms directly exposed from the API and we even have roomMember providers already available. We should refactor the existing providers to reuse these and remove the specific convo/space member providers and replace them accordingly.