Get rid of deprecated hcitool

[rotdrop]

Is your feature request related to a problem? Please describe.
room-manager does not work with up-to-date releases of the bluez-package, e.g. an RPI4 with Ubuntu Focal.

Describe the solution you'd like
Replace the deprecated utils like hcitool and hciconfig by the non-deprecated tools of the bluez package. This might also involce talking to the dbus interface, instead of accessing the Bluetooth controllers directly. I think that also e.g. bluetoothctl uses the indirection via the dbus service.

Describe alternatives you've considered
Well, there are not so many general frameworks available. In particular monitor also suffers from the same problem.

Additional context
See #870

[rmr1014]

Hello. I have recently run into this problem... hcitool has been deprecated, and will not work with Bluetooth 5.0... I would like to see this possibly use bluetoothctl instead, and would even like to help make the change. I just need help with getting started. I have some experience with npm (through developing with Angular).