This replaces the current method of using a Bloom filter in Redis to
check for breached passwords with searching the text file directly using
pts_lbsearch (https://github.com/pts/pts-line-bisect/).

I'm not removing the Redis-based method yet because I want to test the
performance of this first, but this is *far* simpler and doesn't have
the possibility for false positives like the Bloom filter does.