Change controller and route to "Descriptions::Authors"

[nimmolo]

I personally only had the foggiest idea what this controller did when I made the routes last year.

Now that I'm checking it out more closely, it seems it could be better named.

[coveralls]

coverage: 94.394%. remained the same when pulling 15ef4bd71574c6564de377ddb1a4a35b35bc5073 on nimmo-description-authors into a2a9bb1d5866bb5a5c6d2f18d596f824502f72d8 on main.