Empty all repository contents

** Why are these changes being introduced:

* It ends up being easier to rebuild this gem from scratch, rather than
  trying to make piecemeal changes to its infrastructure.

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/engx-175

** How does this address that need:

* This deletes everything in the repository, in preparation for starting
  fresh.

** Document any side effects to this change:

* Some of these files will be restored entirely in a later commit, and
  others will have changes made to them. For now, though, it is easiest
  to just delete everything.

Author: matt-bernhardt