Bug 18050: (follow-up) Force adding FK constraint

Bug 18050: (follow-up) Force adding FK constraint

When there are inconsistent budget_period_id in aqbudgets this patch
creates the table _bug_18050_aqbudgets with the original data, then sets
the column to null and warns the user that there is inconsistent data.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 1193dddd8beb4a10a78e385b221c0f908d92dcf6)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>