Add Netbox Contacts to devices and vm's so hosts can store contact vars

[sol1-matt]

• [x] Make Contact Assignment more accessable
• [x] Look at importing Contact Assignments per Object type.

[sol1-matt]

added in https://github.com/sol1/icingaweb2-module-netbox/commit/07c9a90ac617a391d4f6cae9d25364bc8548a8c9