Improve Custom fields

Request:

Improve Custom field implementation with

- make default workfront data objects available for custom fields, like user name, groups, teams, projects etc

- Update custom field if the they refer to other objects and these objects change

- Support collections and searched in custom fields. Currently, one-to-many relationships, such as project custom fields performing a calculation over its tasks, are not supported.

Benefits:

Increases Data quality and enables flexible implementation of (complex) business logic in Workfront.