[XAM] Rollup of user fixes.

- [XAM] Fix XamUserGetXUID type mask handling.
- [XAM] Fix XamGetUserName return values.
- [XAM] Fix XamGetUserName copy size.
- [XAM] Implement XamGetUserGamerTag.
- [XAM] Fix XamUserCheckPrivilege handling of all users.
- [XAM] Stub XamUserGetMembershipTier.

src/xenia/kernel/xam/user_profile.h

@@ -202,6 +202,7 @@ class UserProfile {
   uint64_t xuid() const { return xuid_; }
   std::string name() const { return name_; }
   uint32_t signin_state() const { return 1; }
+  uint32_t type() const { return 2; /* online profile? */ }
 
   void AddSetting(std::unique_ptr<Setting> setting);
   Setting* GetSetting(uint32_t setting_id);