NFC reading should only be enabled on real terminal devices

[blarz]

NFC tag reading is enabled on terminals and pseudo-terminals (SSH...).
This messes up everything as soon as somebody logs in via SSH.
This blocks the device.

[blarz]

Fixed with #47 for now. Not the most elegant way, but the same hack as in the old matomat ;)

[chca42]

Hm, I see several issues with this hack, e.g., when testing nfc-code, which would now require to run it in tty1. Instead, I would favor a command-line switch, which explicitly enabled nfc, e.g. when run as a service on tty1. If there is no severe argument against it, I will implement it when migrating the terminal to a systemd-based service.

[blarz]

You're absolutely right, hardcoding this makes testing very hard... I was too focused on fixing the issue here.

We could make it a config option? An optional "nfctty" option, which could be left empty.
What do you think?

[blarz]

See #51 for an interim solution until the systemd thing is deployed.

[blarz]

See #55 for the argparse version