Cleanup and Adding Indexes

@bdigital I made some updates to your scripts to improve our own load process. The code is far from perfect (compositionally, test coverage etc), but it's better than it was.

In particular, I added support for the "date" data type in Mysql and it now ports over to the date type in postgres.

This PR adds support for bringing over indexes from mysql into postgres.

This PR changes a lot of the code's organization into functional parts. It's still **very** much procedural code, but the concerns are at least pushed into their own files.

This PR adds some error messaging if one or more columns can be ported from mysql to postgres.

Finally, I added some option parsing so it's a bit more extensible than it was.