Unify the on-AFS perlmodules with those already in GIT.
`/afs/cern.ch/project/afs/perlmodules/` will contain a checkout of the
"master" branch, as well as (ignored) legacy files.

* update README.md
* remove RCS headers from already-in-GIT modules (so rcsedit no longer
cares about them)
* git-ignore old crufty non-git files found on AFS