NXP-12390: add new MessagesRenderer rendering FacesMessages
through jQuery Ambiance plugin.

Use it in the 'message_banner.xhtml' template to render global messages.

Conflicts:
	nuxeo-platform-ui-web/src/main/resources/OSGI-INF/deployment-fragment.xml
NXP-12390: expose 'adminMessageModificationDate' variable
NXP-12390: use 'className' instead of 'cssClass'
NXP-12390: use 'className' instead of 'cssClass'