cellGcmSys and lv2 updates

* Implemented `cellGcmGetNotifyDataAddress` and `sys_ppu_thread_rename`.
* Some changes and refactoring in Report and Memory mapping related GCM functions.
* Fixed some issue that prevented .ELF files from being assotiated with RPCS3.

Thanks again to @3141card (a.k.a. picard) for all the reverse engineering done in `cellGcmSys` and `sys_rsx` functions.