Feature: Link Contact with other contact(s)

[KaiDol]

As a user I would like to link a contact with one ore more other contacts.
I would also define a relationship status with the link based on preconfigured settings.
Examples:

• Contact A is Contact B's boss:
  ** Contact A relationship status is "gets reports by"
  ** Contact B relationship status is "reports to"
• Contact A is contact B's spouse
  ** Contact A relationship status is "spouse"
  ** Contact B relationship status is "spouse"
• Contact A is contact B's assistent
  ** Contact A relationship status is "assists"
  ** Contact B relationship status is "is assisted by"

The list of opposite relationship statuses should be set somewhere in settings of that feature and only be adjustable by admins. It should also be imported and exported as xml file to be easily adjusted.