Add expireTime and alert status history
Add expireTime and alert status history

mrkeng/alerta,skob/alerta,mrkeng/alerta,guardian/alerta,skob/alerta,guardian/alerta,skob/alerta,mrkeng/alerta,0312birdzhang/alerta,guardian/alerta,0312birdzhang/alerta,guardian/alerta,skob/alerta,mrkeng/alerta,0312birdzhang/alerta