* modernize DB-Types
- long term: should be split in class that describes the DB-Type and container class that handles multiples
* make unchanging filter props static, allow lookup of criteria indizes through filter
* move username/mail/password checks to util and make them usable as input filter
* create php classes, each mirroring a js object
* each frontend class implements __toString and json_serialize and as such can be directly used by the template
* also allows for sane object creation before js screams in agony
* usage TBD
