build-steps.d/1200_create-debian-packages: using all options for gpg from https://github.com/ioerror/torbirdy/blob/master/gpg.conf for key generation of local signing key
build-steps.d/1200_create-debian-packages: using all options for gpg from https://github.com/ioerror/torbirdy/blob/master/gpg.conf for key from https://github.com/ioerror/torbirdy/blob/master/gpg.conf for debuild
added CONTRIBUTING.md