OF-1383: Add library removed from Java 11 for backwards compatibility.
OF-1383: Add library removed from Java 11 for backwards compatibility.

Openfire uses javax.xml.bind.DatatypeConverterImpl#DatatypeConverterImpl, a class that has been removed from Java 11.

This commit adds a library that provides this class, JaxB API, as a dependency to XMPPServer. This makes the class available in Java 11.

speedy01/Openfire,guusdk/Openfire,akrherz/Openfire,guusdk/Openfire,GregDThomas/Openfire,akrherz/Openfire,guusdk/Openfire,igniterealtime/Openfire,speedy01/Openfire,akrherz/Openfire,speedy01/Openfire,GregDThomas/Openfire,guusdk/Openfire,GregDThomas/Openfire,akrherz/Openfire,igniterealtime/Openfire,GregDThomas/Openfire,igniterealtime/Openfire,igniterealtime/Openfire,GregDThomas/Openfire,guusdk/Openfire,igniterealtime/Openfire,speedy01/Openfire,akrherz/Openfire,speedy01/Openfire