Bug 4985: Edit a calendar entry for all branches

Bug 4985: Edit a calendar entry for all branches

This patch adds functionality to calendar tool to
make edits or deletes to all branches at once.

To test:
-Apply patch
-Add holiday for a library and copy it to all or some
libraries
-Edit previosly made holiday (edit, delete etc.) and
check out "Copy changes to all libraries." checkbox
=> Changes are made to all libraries sharing changed
holiday

Sponsored by: Koha-Suomi Oy

Signed-off-by: Christofer <christofer.zorn@ajaxlibrary.ca>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>