manger: log force power state changes

Emit a log message when the force power state changes, which also
includes changes to the support state, i.e. if support or not.
4 jobs for 0.7 in 4 minutes and 12 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #71226
alpine

00:00:35

passed #71224
arch

00:02:24

passed #71225
debian

00:04:11

passed #71223
fedora

00:03:07

85.0%