qtd3dservice: Remove registry options

As the service is automatic now, remove these options before the
utility is released these become "API".

Change-Id: I710990d85d9efe3be06ab07b9c73547975c3f78d
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
qtd3dservice: Switch to HKLM for appx registry lookup

This works in service mode; the HKCR lookup did not.

Change-Id: Ic4f81f1cb78e03ba8dbde87edaa14ad94b092df5
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
qtd3dservice: Remove Windows Service mode

Removes -install/-remove options and all traces of the Windows
Service API usage and credentials utilities. The -direct option has
also been removed and direct starting has become the default behavior.

This was a failed experiment. Even after solving the problems with
running the service as the local user, it was discovered that the
required session objects were inaccessible outside of the service,
making emulator support unattainable in service mode. Furthermore, the
direct mode evolved to match the service mode's device trigger
capabilities, making the service mode more obselete.

Change-Id: I458246086f9e46005ce2a30a6eea07fdc94a4da4
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>