Prepare front-end

Populates the front-end with Ajax calls to the expected API paths, with
the expected data. Intended to act as a sort of end-to-end test for
creating and modifying an OptionSet.
Implement OptionSet creation

Adds the "POST /optionset" path
Move "PUT /controller/id" to subclasses

We had a conflict between id being long and Guid, so we move it down to
the subclasses instead. Still rejects all calls as "405 Method Not Allowed"