rfkill was subsumed by util-linux in 2017 [1], and the upstream has not
been updated in over 5 years [2]. This package shadows the rfkill from
util-linux, so it can be completely removed with no breaking changes,
because util-linux is in the base package set in nixos/system-path.
[1] d17fb726b5
[2] https://git.sipsolutions.net/rfkill.git/log/
b63b5eda68