Bug 25032: Make existing controllers use unhandled_exception

Bug 25032: Make existing controllers use unhandled_exception

This simple patch removes 'just in case' handling of specific exceptions
and makes the current routes controllers use the unhandled_exception helper.

Most possible exceptions are already catch by our tools (Koha::Object,
etc) and the existing code is not looking for known possible exceptions
but has just been copied and pasted since our beginings.

Anytime a situation in which an unhandled exception is caught, we (the
devs) should report it and specific exception handling discussed and
solved. But this has just been useless scaffolding so far.

To test:
1. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/*.t
=> SUCCESS: Tests pass
2. Apply this patch
3. Repeat 1.
=> SUCCESS: Tests still pass
4. Sign off :-D

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>