dcache-webadmin: add select/deselect all to ActiveTransfers and PoolUsage

As per feature request. See http://rt.dcache.org/Ticket/Display.html?id=8047.

I am unsure whether this should be ported to 2.6 or not.  I will go ahead an post a separate patch, since it must be applied without the changes made to master having to do with auto-refresh.

Testing:

Deployed and tested by clicking and submitting.

Target: master
Patch: http://rb.dcache.org/r/6164
Require-notes: yes
Require-book: no
Feature-req: http://rt.dcache.org/Ticket/Display.html?id=8047
Depends-on: 6061
Depends-on: 6062
Acked-by: Dmitry

RELEASE NOTES:

Adds select/deselect all on lists on the Pool Usage and Active Transfer pages (when in authorized admin mode).