Transform rel type

This changes the default relationship type to UPCASE and removes the leading `#`. I'm doing a PR into the metadata branch because it uses these changes as a basis but it's significant enough that I didn't want to merge without talking it over first.

The way it works is pretty simple. `config.neo4j.transform_rel_type` and `:upcase`, :downcase`, `:legacy`, :none`. Using it within the code requires you to clear two variables... we might want to change that. I updated specs to expect `:upcase` as default and added a small file of unit tests that demonstrates how it changes based on the setting. I think we should probably add an e2e test that shows it in practice on a real model.