Bug 10126: Remove my variables at module level

Bug 10126: Remove my variables at module level

In C4::Reports::Guided, a lot of variables was defined at module level
and reused in subroutine.

I didn't find any problem with Plack, so I'm not sure this patch is
useful.

Test plan:
Verify there is no more ^my in the module and you don't find any
regression with the guided reports tools (with and without Plack)

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
I'm unsure if this is needed, but I have verified it causes no
regressions

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
No regressions spotted. I'd prefer this code to be fully refactored of course :-P