Break HolyOrders into modules

[crantila]

I've had this in my mind for a while, and I've already started doing it. Now I'm writing it down so it's GitHub Official.

I'm going to break HolyOrders functionality down into the following submodules by purpose:

• configuration for loading, verifying, updating, and saving persistent data
• current for determining whether resources must be updated (i.e., whether they are current)
• drupal for downloading resources from Drupal
• drupal_to_solr for converting resources for use by Solr
• solr for uploading resources to Solr