Refactored ContentBroker to User, new Role Class added, used Spring
Security in DAWEB
new Role Class added
Merge branch 'master' of https://jenspeters@github.com/da-nrw/DNSCore
Merge branch 'master' of https://jenspeters@github.com/da-nrw/DNSCore
This commit will need database changes and might break login to daweb3
with older users on already running systems.

Refactored contractor->User, added Spring security now, changed model