[username parser] Load usernames from `last` for LDAP users

AD/LDAP users are not reported into `lastlog` generally, however they
are reported in `last`. Conversely, `last` does not report local users
who have not logged in but still exist.

In order to obfuscate both kinds of users, we need to look at both
sources.

For this, first allow parsers to specify multiple prep files. Second,
update the username parser to search through all `lastlog` collections
as well as the `last` collection.

Also includes a small update to the username parser's prep loading logic
to ensure we are iterating over each username discovered only once.

Signed-off-by: Jake Hunsaker <jhunsake@redhat.com>

0 files changed, 0 insertions, 0 deletions