Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
Because it's confusing when the dialog shows last target value, but it
doesn't apply when you start tuning.
Also the last values are remembered in DRAWING_TOOL::PlaceTuningPattern
now, instead of global variables.
Related: https://gitlab.com/kicad/code/kicad/-/issues/18979
(cherry picked from commit a950d55cb23724783187663622448b9282d75a41)
