Indicate microphone and camera hardware kill switch state
This needs https://source.puri.sm/Librem5/linux-next/-/merge_requests/77 . I went for listening on /dev/rfkill
until we sorted out the interfaces on the kernel side. Once that is done we can move to g-s-d. The fact that currently only the mic icon is shown is a limitation on the kernel side.
We likely want a nicer icon at some point but currently helping people along to make sure the other end can hear them is prio 1 ;)
Closes: #40 (closed)