REPUBLIC v. AWUTU SENYA TRADITIONAL COUNCIL; EX PARTE NENYI AMU II State proceeding—Prohibition—When applicable—Remedy available to prevent inferior court or governmental agency acting judicially from exceeding jurisdiction—Meaning of acting in "judicial manner"—Traditional council engaging in purely deliberative business except when sitting by way of judicial committee—Whether packing of council with unqualified persons judicial act—Criterion for determining whether prohibition appropriate.