Create a new field definition.
Note: The field definition needs to be assigned to a custom field group by using the 'types field group add_field' command.
Note: This may not work properly for field types that require specific configuration and it may need to be extended.
--domain=<string> : Element domain of the field group (posts|terms|users). Only the posts domain is supported at the moment.
--type=<string> : Field type slug as defined in Toolset_Field_Type_Definition_Factory.
--slug=<string> : Custom field slug. Must be unique within the given domain.
[--name=<string>] : Display name of the custom field. If not provided, the slug will be used instead.