Update to allow use of RFM69HCW variable frequency transmitter

[sdb9696]

Hi there, this PR is not quite ready for merge as it contains some unnecessary changes to locations in the services etc but I wanted to gauge whether you had any interest in accepting the change before I put more effort in on that and the readme etc. There are a few old PRs out there on this repo so I'm not sure if you're still active on this @Nickduino.