webadmin: Render Networks subtab columns sortable

Turned on default text column sorting for all relevant subtab columns
under the networks main tab.

Change-Id: I0e95f529114e62536de0a4f13e8acb20eb6e651d
Bug-Url: https://bugzilla.redhat.com/1120054
Signed-off-by: Lior Vernia <lvernia@redhat.com>