getfedora: render coreos downloads page using stream.json
Fetch stream.json from the builds.coreos.fp.o URL, for the
testing stream.
Add rendering of the artifact data from stream.json, based on
the sample at https://github.com/coreos/fedora-coreos-tracker/pull/207.
Use Vue.js on the coreos downloads page, and pull in the dependency
through /static/js/vue.min.js. This integrates with existing
templating and translation support, by enclosing JavaScript variable
bindings in raw blocks, and specifying translatable text within
translation blocks.
Add a brief description of Fedora CoreOS to the coreos Overview page,
and link to the coreos Overview page from the front page.
Signed-off-by: Robert Fairley <rfairley@redhat.com>