Bug 12194: Add option 'Oblique title' in labels

Bug 12194: Add option 'Oblique title' in labels

This patch adds a checkbox on Label creator
to use or not an oblique variant of main font
for title

Also fix font selection for title in case an
oblique variant is used.

To test:
Before patch
1) Go to Tools > Label creator
2) Create a new layout, default values but select
any 'Oblique' variant for main font and
'Biblio/Barcode' for layout type
3) Go to Manage batches, create a batch, add items,
export PDF, download
4) Check logs, you must find a line with
'ERROR in koha-conf.xml -- missing <font type="COO">'
for example if main font Courier-Oblique

5) Open PDF, title could be right but not using selected font

After patch
6) Apply the patch
7) Run updatedatabase.pl
8) Repeat 1-2, note new checkbox 'Oblique title',
default checked
9) Repeat export, no new warnings on log
10) Create a new layout or edit an existent one,
uncheck 'Oblique title', save, export again
Check PDF has non slanted title

Followed test plan, works as expected. (See comment #11).
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>