…ntend to operate against

This allows clients who only have a partial representation of a resource to use
PUT operations to replace only the triples they are aware of, or provide hints
to the server about what triples they intend to operate on (for e.g. PATCH)

e.g.:

PUT /a
Prefer: handling=lenient;
omit="http://fedora.info/definitions/v4/repository#ServerManaged"

... only non-managed server properties ...

or

PUT /a
Prefer: handling=lenient; received="minimal"

... only the minimal representation ...

Add a Preference for ServerManaged (and allow clients to exclude Server Managed properties on update)

…use of URIs until the tombstone is also removed

Add Tombstone resource when a resource is deleted, preventing the re-use of URIs until the tombstone is also removed

Resolves: https://www.pivotaltracker.com/story/show/80853212