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

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

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

Change-Id: I8ccb2acd6f6593938600c456814c3cfcb316335a
Signed-off-by: Daniel Erez <derez@redhat.com>