Merge branch 'v0.6-a/patched-base' into v0.6-a/patched-keycodes

Merge remote-tracking branch 'wochap/v0.6-a/output-power-management' into v0.6-a/patched-base

implement the output power management protocol

inspiration: https://github.com/djpohly/dwl/wiki/outputPowerManagement