webadmin: Disks main-tab: sub-tabs resizable columns

Sub-tabs under Disks main-tab now support
resizable columns.

* Invoked enableColumnResizing() on each sub-tab.
* Added a static width value for each column.

Change-Id: Ia6ac016dd8e8428f17c873cd29d7e46170dadcc4
Signed-off-by: Daniel Erez <derez@redhat.com>