"Incompatibility might consist in so permanent and complete a commitment to the performance of non-judicial functions by a judge that the further performance of substantial judicial functions by that judge is not practicable. It might consist in the performance of non-judicial functions of such a nature that the capacity of the judge to perform his or her judicial functions with integrity is impaired. Or it might consist in the performance of non-judicial functions of such a nature that public confidence in the integrity of the judiciary as an institution or in the capacity of the individual judge to perform his or her judicial functions with integrity is diminished."