eupspkg.sh: look for ./ups/eupspkg.cfg.sh

Renamed to make it cleared from the name that this is a configuration file
that should not be sourced or executed directly. Still kept the .sh suffix
to indicate this must be a bash script.
renamed lib/eupspkg.default back to lib/eupspkg.sh
eupspkg.py: code and doc updates for eupspkg[.default->.sh] rename