Bug 25381: XSLTs should not define entities

Bug 25381: XSLTs should not define entities

Bug 23290 explicitly disabled entity expansion during XML parsing for security reasons.

However, many XSLTs define the following entity:
<!ENTITY nbsp "&#160;" >

They don't use the entity &nbsp, but its presence could lead to confusion.

Signed-off-by: Eden Bacani <eden.bacani@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
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 10c08b6552c7063c4c029701018d6f54e6549acb)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>