dfk on github -> dual-function-keys on gitlab

Last step of the migration. Thanks for getting me set up @oblitum

I should make some contributions to interception tools itself.

Looking at the issues:

#3 (closed) seems very reasonable and useful - YES

#22 (closed) does not have a reproducer - NO

#15 (closed) is a valid use case - I might just productionise my trivial keycodemapper that solves all cases: https://github.com/alex-courtis/interception-widgets

#4 (closed) doesn't really fit interception-tools, which is all about udev - NO

Unless you have any better suggestions, I'll do #3 (closed) then #15 (closed).