Bug 29311: Forbid editing biblio info when creating suggestion for biblio

Bug 29311: Forbid editing biblio info when creating suggestion for biblio

When creating a suggestion for an existing biblio, biblio info like
title or author should not be editable.

Test plan:
1. Enable system preference 'suggestion'
2. Log in at OPAC
3. Go to a biblio record detail page
4. Click 'suggest for purchase'
5. Notice that all fields can be modified (title, author, ...)
6. Apply patch
7. Repeat steps 2 and 3 or refresh the page
8. Verify that the biblio fields cannot be modified now. The only fields
   that should be editable are: quantity, item type, library, reason for
   suggestion, and notes

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Laura Escamilla <laura.escamilla@bywatersolutions.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>