Add a REST endpoint to get a tarball of a CAS directory
Context
bgd-browser needs to support downloading tarballs of directories from CAS, and this is only really feasible to support on the backend, rather than in the browser client.
Acceptance Criteria
This is done when the REST API added in #362 (closed) can construct and return tarballs of directories from CAS.
Consider whether the following are required, and complete if so:
-
Unit tests -
Metrics -
Documentation update(s)