Bug 32935: (bug 13614 follow-up) Remove unused basketgroup.js

Bug 32935: (bug 13614 follow-up) Remove unused basketgroup.js

Bug 13614 removed it. On bug 31056 we noticed that one function was
still needed but we copied it in the corresponding .tt

Now this JS file is no longer used and should be removed from the
codebase

Test plan:
  git grep basketgroup.js
must not return anything

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit a48bce7c3bd26a52b85384d725101929b3981c5c)
Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>