add announcements composable and dialog component

frontend/lib/icons/icons.ts

@@ -19,6 +19,7 @@ import {
   mdiBookOutline,
   mdiBowlMixOutline,
   mdiBroom,
+  mdiBullhornVariant,
   mdiCalendar,
   mdiCalendarMinus,
   mdiCalendarMultiselect,
@@ -181,6 +182,7 @@ export const icons = {
   bellAlert: mdiBellAlert,
   bellPlus: mdiBellPlus,
   broom: mdiBroom,
+  bullhornVariant: mdiBullhornVariant,
   calendar: mdiCalendar,
   calendarMinus: mdiCalendarMinus,
   calendarMultiselect: mdiCalendarMultiselect,