feat(notification): replace mdl snack-bar by md snack-bar
feat(notification): replace mdl snack-bar by md snack-bar

get rid of mdl components, replace mdl snack-bar service by md's snack-bar component

bwsw/cloudstack-ui,bwsw/cloudstack-ui,bwsw/cloudstack-ui,bwsw/cloudstack-ui