Split mapping from Access and Helper classes into it's own. Fully test them, too.

remove unused methods

split mapping methods off from Access class

fix DB query handling

move 'clear mapping' methods from static helper to new mapping class

add tests

test directly with DB

finishing tests and fix return value from setDNbyUUID

add corresponding class for groups and make abstract test class neutral. helper tests is now obsolete as the tested functions were moved to the new mapper class.