XWIKI-9136: Rest API JSON does not retrieve inherited fields
* Use Jackson converter for the JSON representation.
* Use JAXB converter for the XML representation.

(cherry picked from commit 90f35335d9735ac69763775150720351352323de)
XWIKI-9936: The tree view doesn't load on IE11
* Request JSON REST resource representations to avoid dealing with XML namespaces as IE11 doesn't support document.createNSResolver

(cherry picked from commit 74a81a2669e40de0b04496eb084fd09019d81694)