Bug 33961: Remove built-in offline circ tool

Bug 33961: Remove built-in offline circ tool

The tool has not been updated and is no longer working with modern
browser.

It should either be rewritten/adjusted or removed. Given that we didn't
get complains its non-functional status, bugs related to this tool
didn't get attention, and the community is lacking resources, I am
suggesting to remove it and redirect users to the koct FF plugin that
is known to be working.

Test plan:
See bug 10240 and use `git grep` to confirm that we are removing all
tracks of this feature.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>