map-agent: add UBUS method for 'assoc-status-notify' CMDU
UBUS method for 'assoc-status-notify' CMDU: "assoc_notify":{"bss_status_list":"Array"}
i.e. ubus call map.agent assoc_notify '{"bss_status_list":[{"bssid":"11:11:11:11:11:11","status":0},{"bssid":"12:12:12:12:12:12","status":1}]}'