Add discussion of database management systems

One of the core points of confusion from the minute cards on the
first run of the course was how what we had learned related to
other DBMSs. This makes clear that what we are teaching is general
to all of these systems.
Replace mention of ODBC with discussion of other DBMSs

Mentioning ODBC to combine Access/Filemaker with SQLite for
QA/QC was too advanced. It's better to replace this with a simple
discussion of alternatives to SQLite and their pros and cons.

This will also help reemphasize that what we've taught then
generalizing across DBMSs.