LDEV-4402 Remove obsolete XPP3 and XMLPull librariesThe libraries have been used by earlier versions of XStream. They arenot needed for latest XStream and Java 6+.Deserialized classes must implement a no-arg constructor.
LDEV-3275: Make XStream use enhanced mode in which it can instantinate classes without no-arg constructors. This requires Oracle's JVM to be used, but it is a requirement of LAMS anyway. Otherwise multiple LAMS classes (mainly DTOs) would have to be given no-arg constructors or implement Serializable.
LDEV-3275: Add missing dependencies. Update XStream to version 1.5.0, and its corresponding libraries. Reimplement LD attachment importing. Reimplement Content Repository credential check. Moja joda-time library to separate folder as it is not a part of XStream deployment anymore, but it is still needed in LAMS code.