This takes advantage of generics, and generally clears up a lot of
inconsistencies and quality-of-life issues.
Start of db rework: clean up, start generics, improve tests
Write some nice aspirational package docs
Rework and document the db API
Tests still pass, at least...now for everything else
Update all callsites of db functions
Finish converting all callsites
Not too bad actually! Centralizing access into the helpers makes a big
difference.
wtf it works
We don't need to do this any more, since our database backups now
include the migration table. The seedfile command also no longer
requires the user to type a password.
This also prevents the Discord history bot from running when it has no
credentials.