Fine Grained Control Of Multi-GPU Configurations

[macvelli]

My BOINC use case:

• Ubuntu 18.04.1 Desktop running BOINC 7.14.2
• SETI@home
• GPU 0: NVIDIA GeForce GTX 1060
• GPU 1: NVIDIA GeForce GT 1030

I have two monitors connected to the GTX 1060
No monitors are connected to the GT 1030

I would like the ability to:

• Tell BOINC to Suspend GPU 0 when computer is in use
• Tell BOINC to Always use GPU 1 regardless of whether computer is in use or not

Right now the GT 1030 sits idle when I am on my Ubuntu Desktop machine and I would like for it to be crunching away all the time

[RichardHaselgrove]

I think this is a specific use case which fits within the generalised ambit of #41.

[code-kot]

This issue is related to #2993