Merge branch 'gpu_upgrade' into 'master'

Extend the GPU role

The GPU role used to just detect if any driver was installed and skip installation if one was found
it will now execute nvidia-smi to determine the current driver version and compare it against the desired
driver version, installing in the case of mismatch

Note that if an existing driver is installed, the nvidia persistence daemon must be stopped before installation can proceed

See merge request !114