Bug 10703: Add db documentation for biblioimages table

Bug 10703: Add db documentation for biblioimages table

This patch adds db documentation to the biblioimages table.

To test:

Apply patch
Review kohastructure.sql to be sure that the documentation is there

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 801d8237d80d7079f3355da18ef18c60b7f37325)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>