follow our formatting convetions.
- add support for aliases, amd.home, master.passwd and netgroup maps
[initially from openbsd, reworked as above]
- if INSECURE != "yes" then the passwd.by* maps will not contain the
encrypted version of the passwd - privileged clients will request
info from the master.passwd.by* maps.
FreeBSD originally implemented this, and & OpenBSD supports it too.
[from openbsd].
By default, passwd maps are INSECURE, but in a *BSD-only environment,
this could be disabled to allow for a [slightly] higher degree of
security from non-root users...