Added a copy of the notes from NFCpy

Reminds the configuration of udev for the NFC devices to be usable
Added configuration constants and parser
Added configuration generation script

Textual menu-based utility script to generate a configuration file
NFC devices are handled by a utility class

- NFC on-connect is blocking: call it in a thread
- removed signals handling, as it was messing with Ctrl+C
- better NFC association handling