Feature/stable repo links

Hi @barnabyalter 

All tests are passing here now, but deploying this will require incorporating the companion pull request in the findingaids_ead repo and deleteing/reloading tamwag/tamiment, archives/universityarchives, bhs/brooklynhistory, and nyhs/nyhistory.

I had one question, which I'm including as an inline comment in the code below.

Let me know if you have questions or comments

cc @NYULibraries/finding-aids 
This is the bit I had a question about. I needed to be  able to test a search that _wasn't_ on the root path, so was being stymied by the ensure_root_path. Should I have set up a separate search step for my case? It seems like pushing to root should be left alon in the search steps and handled during given, but perhaps you had another reason for setting it up this way?