feat: default to schedutil governor instead of fixed clock speed

[frysee]

As a result of this discussion⁠, I'm currently testing the following:

• NextUI will now default to schedutil instead of userspace + fixed 2000Mhz when initially launching into paks.
• All of the base paks then overwite as needed, i.e.:
  • nextui/minarch with auto scaling (or whatever the user set as preference)
  • basic menu paks with lower fixed clock (CPU_SPEED_MENU).
• New cpufreq.sh helper for third-party paks that might want to control CPU clock speed without directly interacting with low-level system specifics:

Usage: ./cpufreq.sh -p <profile> [-f <freq>]
Profiles:
   performance   - max speed
   powersave     - min speed
   ondemand      - ondemand governor
   schedutil     - schedutil governor (if supported)
   interactive   - interactive governor (if supported)
   conservative  - conservative governor (if supported)
   reset         - restore defaults (all cores online, default min/max, default governor)
   status        - show current governor, freq, active profile, and CPU online status
   list          - list supported governors
   freq          - set exact frequency (requires -f <Hz>, userspace governor)