Refactor of OmniAuth hash mapper and Aleph Patron to DRY up code and make more logical and readable:

OmniAuthHash/ProviderMapper
* The 'extra' attributes field under properties shouldn't be merged with anything downstream. Push all properties into 'properties' field
* The API path for Aleph identity properties should be aleph/properties not aleph/properties/extra
* Cleanup all provider mapper initializers so we don't have to force redefine of any attrs that can be defined with defaults in the super class
* Move institution logic from provider mapper to Aleph::Patron and utilize Patron object in the provider mapper
* Increased testing coverage and documented confusing functions
Changed status and type to patron_status and patron_type respectively for Aleph::Patron attrs
Merge pull request #60 from NYULibraries/chore/cleanup-aleph-identity

Refactor of OmniAuth hash mapper and Aleph Patron to DRY up code and mak...