Add support for new oracledb package

[troyswanson]

It looks like Oracle is changing their driver package to be (mostly) pure Python, and is changing some of the interfaces.

Here's a link to some documentation that shows all of the differences:
https://python-oracledb.readthedocs.io/en/latest/user_guide/appendix_c.html

[zschumacher]

Thanks for the issue, I’ll take a look at adding that this weekend!

[troyswanson]

@zschumacher I made a pretty basic PR that's just a copy/paste job from the cx_Oracle implementation. I'm happy to continue working on it based on any code review comments you have.

[zschumacher]

@troyswanson PR looks great, just need to update docs. Let me know as you come across anything that wasn't obvious from a contribution standpoint and I can get some contributing docs up.

[troyswanson]

Thanks! It's been generally pretty easy so far. Had to figure out how to install extras using Poetry.

Also, switching to using the new oracledb driver as the default would be helpful for anyone getting started since it doesn't require the Instant Client to do basic database operations.

[zschumacher]

yeah the instant client is a pain for sure. I opened #28 and will consider doing that when I 1.0