Bug 21591: Check for record level item type issues too

Bug 21591: Check for record level item type issues too

To test:
1 - sudo koha-mysql kohadev
2 - UPDATE biblioitems SET itemtype = NULL where biblionumber = 1
3 - UPDATE items SET itype = NULL where biblionumber = 1
4 - perl misc/maintenance/search_for_data_inconsistencies.pl
5 - Notice warnings
6 - Apply patch
7 - Undefined itemtype on bibliolevel is now warned
7 - Test also with itype=""

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>