Bug #5329 : adding a new rules around WYSIWYG attachment management.
When updating a WYSIWYG attachment for a language with an empty content, the content for language is not saved but deleted. After that, if no content for any language exists for the attachment, then it is deleted from the JCR.
(adding some unit tests around the WYSIWYG controller)
(adding a List Object for SimpleDocument to centralize common behaviors)
Empty WYSIWYG documents are considered as non existing on display.

Conflicts:
	lib-core/src/main/java/org/silverpeas/attachment/SimpleDocumentService.java
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentConverter.java
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentRepository.java
Bug #5479 : JCR copy and move problems
- adjusting some code after cherry pick of the commit from core-5.14.x
- fixing the case of the copy that did not work too (history of versions was not respected, i18n was not supported, date of a version was not the one of the original but the date of the copy action !)
- fixing the case of the move
- upgrading the simple document access controller in order to take in account the versions of attachments
- improving the mechanism of universal link associated to attachments
- handling the language content for versioned attachments

Conflicts:
	lib-core/src/main/java/org/silverpeas/attachment/model/HistorisedDocument.java
	lib-core/src/main/java/org/silverpeas/attachment/model/SimpleDocument.java
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentConverter.java
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentRepository.java
	lib-core/src/test/java/org/silverpeas/attachment/repository/HistorisedDocumentRepositoryTest.java
	war-core/src/main/java/org/silverpeas/attachment/web/VersioningRequestRouter.java
	war-core/src/main/java/org/silverpeas/attachment/web/VersioningSessionController.java
	war-core/src/main/webapp/attachment/jsp/publicVersions.jsp
	web-core/src/main/java/org/silverpeas/accesscontrol/SimpleDocumentAccessController.java

Conflicts:
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentConverter.java
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentRepository.java
Bug #5479 : JCR copy and move problems
Taking into account a new detected problem around the copy of a versioned attachment that had several language contents before to be turned into versioned attachment.
The problem was that the result copy of this kind of attachment was keeping only one of the several language contents for its initial version.

Conflicts:
	lib-core/src/main/java/org/silverpeas/attachment/repository/DocumentRepository.java