Add logic to GET artifacts via old or new UUID (#587)

* Move range.go into sharding package to avoid import cycles

Signed-off-by: Lily Sturmann <lsturman@redhat.com>

* Change name of FullID to EntryID

Signed-off-by: Lily Sturmann <lsturman@redhat.com>

* Add unit tests for sharding package

Also add a few helper functions and update names.

Signed-off-by: Lily Sturmann <lsturman@redhat.com>

* Add logic to GET artifacts via old UUID or new EntryID

Signed-off-by: Lily Sturmann <lsturman@redhat.com>

* Add e2e test for longer EntryID

Signed-off-by: Lily Sturmann <lsturman@redhat.com>