Connection urls

[d-r-q]

Actual behavior: user should manually instantiate storage and pass it to qbit

To decouple user from implementation implement qbit connection factory function that accepts string parameter (kind of "qbit:fs://tmp/qbit/mydb") and internally creates corresponding instance of storage.

Implementation should also provide Storage implementation registration end point, so user, who implemented custom Storage may register it.

This feature requires some way to automatically discover service providers and I'm not sure it may be implemented on Native and JS platforms.