login.defs: Add LASTLOG_UID_MAX variable to limit lastlog to small uids.

login.defs: Add LASTLOG_UID_MAX variable to limit lastlog to small uids.

As the large uids are usually provided by remote user identity and
authentication service, which also provide user login tracking,
there is no need to create a huge sparse file for them on every local
machine.

fixup! login.defs: Add LASTLOG_UID_MAX variable to limit lastlog to small uids.