Bug 18674: Added timezone information to about page

Bug 18674: Added timezone information to about page

Before patch: No timezone section
After patch: timezone section at bottom of
             Server information tab.

Actual is what is being used. Config overrides environment variables.
So if there is confusion why the environment variables aren't working,
it will be visible why.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>