Add dynamic CPU governor selection

Start using powersave on clients (laptops)

v211: Restore settings to desktop.

Most of the settings were silently removed from desktops, which was
never intended. This restores most of the settings for desktops while
still making systems generally server-tuned by default unless identified
as a desktop specifically.

210: Remove somaxconn override.

Previously, the default was 128, which we conservatively increased
to a higher value. 5.4.x kernels however have a value of 4096 by
default, meaning we *decrease* the amount, unintentionally.

It's possible that this may affect something negatively, but, if
that is found to be, we can address it when needed. This should
largely be a positive change in most cases.

209

v209

208

208