Feature #5157 - Modifying the database model of the Gallery application.

Conflicts:
	gallery/gallery-ejb/src/test/resources/com/silverpeas/gallery/dao/media_order_dataset.xml
Feature #5157 - PhotoPK to MediaPK.

Conflicts:
	gallery/gallery-ejb/src/test/java/com/silverpeas/gallery/dao/PhotoDaoTest.java
Feature #5157 - Creating Media model.
Adding Gallery component setting provider (and wiring the folder name prefix of a media).