Feature Enhancement
Expose Default Operator for Filter fields

Current behavior
Apart from setting FilterExpression to render filed with a certain operator, there is no option for setting a Default Operator for the fields

.FilterExpression(f =>
      {
          f.Add(p => p.FirstName).Contains("Jeremy");
      })

The above renders the Contains operator initially but if you change the field and return back to the FirstName field the operator is no longer Contains.

Expected/desired behavior
Default Operator for FIlter fields shall be exposed

Environment
Kendo UI version: all
Browser: al