And update the feature description.

And a lot more. Fleshed out some services.

The saving part is almost working. Need to get FillPDF file contexts
being saved properly. Then, I need to ensure that access
checking on the files works like I expect. I will probably have to
implement some hook or another.

Woohoo!

Still more old-style syntax lurking around.

Gotta return the response!

I'm getting an error when I actually try to populate/download the PDF. There is probably
something wrong with the Request object I'm returning. But this is closer.