shell: Handle modern DBusClient in hostname_for_display

Reviewed-by: Stef Walter <stefw@redhat.com>
shell: Simplify HTML

Mostly, move the top navbar out of #content.

Reviewed-by: Stef Walter <stefw@redhat.com>
shell: Host switcher

Reviewed-by: Stef Walter <stefw@redhat.com>
shell: Hide navigation when showing the dashboard

Reviewed-by: Stef Walter <stefw@redhat.com>
shell: Ensure that the plots resize when the host switcher toggles

Closes #1409
Reviewed-by: Stef Walter <stefw@redhat.com>
tools: Use same cockpit.spec as Fedora for our testing

This makes our work easier trying to keep track of what's going
on and where. Use rpm condititionals to build optional parts
of the cockpit.spec file.

Simplify the make-rpms and make-srpms

Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
tools: If JSL is not available allow build to proceed without it

Closes #1432
Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
shell: Export hosts model and make it more useful.
dbus-json3: relaxed subscriptions
shell: Add cockpit.shell.hosts[...].remove()
shell: Add cockpit.shell.host_setup()
WIP dashboard hosts
WIP plots
WIP resize plot
WIP more plots