add custom_field_type field to vocabulary (#1602)
add custom_field_type field to vocabulary (#1602)

SDBELGA-86
superdesk/superdesk-core,superdesk/superdesk-core,petrjasek/superdesk-core,superdesk/superdesk-core,petrjasek/superdesk-core,superdesk/superdesk-core,petrjasek/superdesk-core,petrjasek/superdesk-core