This method allows to create custom field.
Required if type one of: 3 - selectbox; 5 - radio; 6 - multiselect;
Possible values: 0 - case; 1 - run; 2 - defect;
Possible values: 0 - number; 1 - string; 2 - text; 3 - selectbox; 4 - checkbox; 5 - radio; 6 - multiselect; 7 - url; 8 - user; 9 - datetime;
Created Custom Field id.