Qnx: Introduce QnxDeviceProcess

This is helpful for more selective and direct process killing.
Previously, all processes with a given name were killed, and
in some cases stale awk and grep processes were left over.

Change-Id: I4fb3999818062b8c1fdf7dca8a337ef9c158be9b
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>