Pre-Process processing Gator Resources

[jhpierce]

Description

This is a big one - extend the pre-processing functionality to accept:

• a Configuration object
• a repository string

1. Get a Github client, defined in Create a function for building a Pygithub Client #24
2. Run the resources according to the Changeset

For now, simply running the resources is enough. We can tackle the work of queueing work to be post-processed in another ticket.