The overloading only needs to happen for `PUT`s and `POST`s, GETs will work the same for both. There are two reasons I think we should use the same endpoints:

1. In the long run, most things that can be done by manual browsing will probably have a use case for automating, so the /api tree might eventually duplicate the entire uri namespace
2. The vast majority of the work is shared. In most cases, the HTML path and the JSON path will only need to diverge when rendering, and all of the work in the controller itself will be needed and identical for both paths. Currently there's some duplication, as e.g. for `GET /jobset/{foo}/{bar}` essentially the same data is put into `$c->stash->{jobset}` and `$c->stash->{resource}`, but that duplication can be gradually removed once this is merged (I only have it there at all to minimize the chances of breakage). Once we iron some details out and get used to writing actions this way, adding a new endpoint that has both an HTML and a JSON serialization will require no marginal effort on top of what's required to add a new endpoint with just an HTML representation. If instead we keep the URIs separate, adding both JSON and HTML endpoints will require more work than just HTML, which means we'll almost definitely just default to only adding HTML endpoints.