Request: Separate Steam and PlayOnLinux, add Lutris.

[dylanmtaylor]

Is your feature request related to a problem? Please describe.
No.

Describe the solution you'd like
There is a Steam & PlayOnLinux group. I think having Steam, PlayOnLinux and Lutris separately selectable would be more desirable.

Describe alternatives you've considered
Manually installing these software packages is an alternative.

Additional context
Lutris is a fantastic GUI and I think it's superior to PlayOnLinux in many ways. I'd love to have it be exposed via the installer.