removed setting of umask to 077

on OpenBSD, this results in incorrect permissions for install packages
Don't set PKG_PATH on OpenBSD

cdist doesn't detect OpenBSD snapshot releases, and thus incorrectly
sets PKG_PATH. Should rely on /etc/pkg.conf instead.
/etc/sudoers: made closer to stock OpenBSD
added /etc/pkg.conf
install /etc/pkg.conf
set shell for user rfnash to zsh