Some phases of the installer are not always needed so allow setting the
following varibles to skip their respective phases:
BSDINSTALL_KEYMAP_SKIP
BSDINSTALL_TIME_SKIP
BSDINSTALL_SERVICES_SKIP
BSDINSTALL_HARDENING_SKIP
BSDINSTALL_USERS_SKIP
BSDINSTALL_MANUAL_SKIP
If this seems reasonable I have ideas for a few more