[Lvfs-announce] JSON firmware details endpoint

Hi all,

One OEM asked me if there was a JSON endpoint for getting details
about the firmware uploaded to the LVFS so that they could check that
the firmware was in the correct state automatically.

Two hours later, there now is -- showing all the firmware the
username+token can normally see on the LVFS. It is documented in
https://lvfs.readthedocs.io/en/latest/upload.html#automatic-uploads --
if anybody needs anything else please let me know.

Richard.