shell: Don't show mounts that UDisks tells us to ignore

Such as the Docker image and container storage machinery.

Closes #1320
Reviewed-by: Stef Walter <stefw@redhat.com>
Use the term 'package' instead of 'module'

The packages really are just collections of resources, with the actual
html files and javascript files and (soon iframes) providing the actual
modular architecture.

In addition 'modules' is used a lot in the javascript community to do
with module loaders etc. We want to avoid confusion there.

Rename 'module' to 'package' everywhere. And move the modules/ directory
to pkg/ which is shorter and clearer.

Closes #1310
static: jQuery becomes part of the the packages

No jQuery on the login page is the upshot here.

We'll probably unfortunately get to the point where different versions
of component have different jQuery requirements and so on. So jQuery
gets loaded by the packages.

See later commits for a solution that prevents needless copying of
jQuery all over the place.

Closes #1315