A couple who claims NBA player Matt Barnes assaulted them in a trendy Manhattan nightclub is going to sue him, their lawyer said Wednesday. Jasmine Besiso and Myrone Powell say Barnes, 36, who plays for the Sacramento Kings, went berzerk on them at the Avenue nightclub on 10th Ave., said their lawyer, Michael Lamonsoff said. The duo also plans to sue Barnes’ teammate DeMarcus Cousins, Lamonsoff …