Add .mailmap
Add .mailmap

Coalesce together commits by the same person in git-shortlog(1).

For people with different aliases, prefer full names over abbreviations
or nick names. For people with different email addresses, use the most
recent email address.

RonnyPfannschmidt/borg,RonnyPfannschmidt/borg,RonnyPfannschmidt/borg,RonnyPfannschmidt/borg,RonnyPfannschmidt/borg