Add a "self" relation to license status documents

[jotson]

Is it possible to add a "self" relation to license status documents? Something like this in license_status.go:makeLinks():

link := licensestatuses.Link{Href: lsdBaseURL + "/licenses/" + ls.LicenseRef + "/status", Rel: "self", Type: api.ContentType_LSD_JSON, Templated: false}
*links = append(*links, link)

If you're willing, I can submit a PR. Please let me know if you have any special requirements for it.

Background:

We're doing an OPDS2+ODL^1 implementation with LCP for library lending.

When a client performs a "checkout" we ask the lcp server to generate a new license. The ODL spec requires the response to a "checkout" to be a License Status Document. Our problem is that the License Status Document doesn't link to itself so there's no way for the client to query the status again in the future.