OO-1873: replace the deepCopy (java serialization / deserialization ) of the test by a simple XML parsing on the content

OO-1873: reduce number of objects generated by some toString methods, optimize the normalizeFilename to prevent the creation fo 10 compiled regex patterns

OO-1873: for the XSLT transformation for QTI results, replace the synchronized transformer with templates, reduce the StringBuilder <-> String copy paste

OO-1873: replace the listing of booking by a native query optimized for our standard setup, replace the .hbm.xml with annotations, add more fetching overall