Reorganize the contact managment

[scaphilo]

We need to reorganize and rename the entitties in the koalixcrm:
There shall be
Contacts (can be a customer)
Contacts hall be the equivalent to a private person

Organizations (can also be a customer)
Organizations may be any form of legal person (AG, GmbH, Verein, Holding, Coorporation, ....)

Link between Contact and Organizations
contact can work for an Organization
contacts can have a hierarchical position within an Organization
....

Link between Organizations and Organizations

The addresses be linked with contacts and organizations but shall not be hard reference anymore