Fix ISC-Bugs 45340: Statschannel XSL for zones, Traffic

Fix ISC-Bugs 45340: Statschannel XSL for zones, Traffic

In ISC-Bugs 45340, I wrote:

The Statistics channel offers links to Zones and Traffic.
Both produce valid data, but display as blank pages with
a web browser.

Zones never had XSL (I provided the original
implementation, but punted on the XSL).

Traffic has XSL, but it wasn't updated to reflect the
split between IPv4 and IPv6 data.

I've picked up enough XSL to fix my original omission,
and as penance for my sloth, fixed the Traffic bug as well.

(cherry picked from commit 96f0bbd4d51e543881989a6811a82258127a05b5)