Bug 10590 - in opac-topissues limit param is not protected

Bug 10590 - in opac-topissues limit param is not protected

In opac-topissues page, the limit URL argument is directly added to SQL query.

This patch adds protections : limit must only contain digits and must be lower than 100.

Test plan :
- Edit URL to : /cgi-bin/koha/opac-topissues.pl?limit=10&branch=&itemtype=&timeLimit=999&do_it=1
=> You get the results of 10 most cheched-out of all time
- Edit URL to : /cgi-bin/koha/opac-topissues.pl?limit=&branch=&itemtype=&timeLimit=999&do_it=1
=> You get the results of 10 most cheched-out of all time
- Edit URL to : /cgi-bin/koha/opac-topissues.pl?limit=9999&branch=&itemtype=&timeLimit=999&do_it=1
=> You get the results of 100 most cheched-out of all time
- Edit URL to : /cgi-bin/koha/opac-topissues.pl?limit=WHERE&branch=&itemtype=&timeLimit=999&do_it=1
=> You get the results of 10 most cheched-out of all time

Signed-off-by: Robin Sheat <robin@catalyst.net.nz>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 57866d6b67c3f8b29290150f21c71395315a73fe)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>