[Feature] Add tuned support

[francoism90]

Thanks for creating this image! :)

Would it be possible to add tuned (maybe by default in disabled state)?

The reason is that I use this image on my NAS, but in the night I'm not doing anything useful, and switch to powersaver. It also offers an atomic preset package, which also has profiles for CoreOS. It's weird it isn't installed by default.

For the record, these are the overlayed packages I used on my CoreOS bare-metal install (they have more profile targets):

tuned
tuned-profiles-atomic
tuned-profiles-cpu-partitioning
tuned-utils
tuned-utils-systemtap

The reason for asking this as a request, is that you cannot control this in a toolbox. :)