build: Disable parallel make for SELinux

The makefile provided by selinux-policy-devel is not compatible
with parallel make invocation.

Closes #647
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
web: Get upper limit from /proc/meminfo for container resource sliders

Fixes #390
Closes #636

Signed-off-by: Stef Walter <stefw@redhat.com>
 - Rebased and fixed conflict
cockpit: Make ECONNREFUSED also mean "not-found".

We get this error for example when docker is not running, and
previously we showed it as "internal-error".

Closes #639

Reviewed-by: Stef Walter <stefw@redhat.com>
web: Add resource graphs to service details.
web: Add "My Services" tab.

Fixes #631
web: Make service rows slightly prettier.
web: Add start/stop buttons to My Services
web: Change services terminology.
web: Allow adding and removing of Geard services.