Update CREDITS and .mailmap files

Update CREDITS and .mailmap files

Update the CREDITS file using maintenance/updateCredits.php script that
uses `git log` to identify contributors. For each added user it was
checked by hand that no user with the same mail adress but an other
"Real Name" was already in the CREDITS file. This is the case with one
entry, prevent this using .mailmap. Also remove (WMDE) at end of real
name in one case using .mailmap file. Also change version name MW 1.28
to 1.29 while at it.

Change-Id: I4c3bb8c3e5f0c1317ea8711efc4f88e571b0c5c6