git: mailmap can correct names and emails

Using the mailmap feature, git can correct/map the name and/or email of people mentioned (authors and committers).

In .mailmap at the root of the repository:

# Correct name and/or email from name and/or email
Foo Bar <foo@bar.com>           <foo@noreply.github.com>
Foo Bar <foo@bar.com>           <f@bar.com>
Foo Bar <foo@bar.com>     Foo B <f@bar.com>

Now log, show, whatchanged will map names as described by default.