User profile: Add support for querying match statistics

This module is currently only partially supporting the new profile endpoints.
Support for the new calls to query profile match statistics is still to be implemented.

Sample calls:

`rest/userprofile.json?command=gamemode&usn=1&gid=EM`

where `gid` can also be:

- EM
- CL
- CM
- ZM
- ...

