This adds a NixOS option for setting the CPU max and min frequencies
with `cpufreq`. The two options that have been added are:
- `powerManagement.cpufreq.max`
- `powerManagement.cpufreq.min`
It also adds an alias to the `powerManagement.cpuFreqGovernor` option as
`powerManagement.cpufreq.governor`. This updates the installer to use
the new option name. It also updates the manual with a note about
the new name.
Was meant to go into staging, sorry
This reverts commit 57b2d1e9b0dcdd1d25bd2d450174764b9417ffc1, reversing
changes made to 760b2b9048ea775c319cb348d74447a20dea513e.
