Add explicit dbname to mysql properties only for testing purposes

MySQL requires the schema to be in the URL and not a property, so
there's not a good way to read this info in. The tests depend on the
schema, but this may be removed later if it's not needed (I suspect it
isn't now that DataExpress handles schemas under the hood).
Make test setup lazy

In cases where we don't want the proprietary tests to run, we should do
a lazy setup of the fixtures so as not to create connections we won't
(or can't) use and blowing up the test.
Change hard-coded schemas to properties

Schemas are now being read in as properties instead of being
hard-coded. This is more portable for people running in other
environments.
Fix formatting