Use Config::Identity to permit GPG-encrypting credentials

Fixes #77789: Use Config::Identity to permit GPG-encrypted credentials
Don't load Data::Dumper until it is needed
Make Config::Identity optional
tweak changelog
make Config::Identity a non-prereq, too
v0.103005

          Use Config::Identity to permit GPG-encrypting on-disk credentials
          (thanks, Mike Doherty)