Poll history - read only list of polls in current timeline (#10055)

* add settings while under development

* very basic tests for roomsummarycard

* empty poll history dialog and option in room summary

* pollS history in settings

* render an ugly list of polls in current timeline

* readonly poll history list items

* fix scroll window

* use short year code in date format, tidy

* no results message + tests

* strict fix

* mock intldatetimeformat for stable date formatting

* extract date format fn into date-utils

* jsdoc

src/DateUtils.ts

@@ -269,3 +269,16 @@ export function formatPreciseDuration(durationMs: number): string {
     }
     return _t("%(value)ss", { value: seconds });
 }
+
+/**
+ * Formats a timestamp to a short date
+ * (eg 25/12/22 in uk locale)
+ * localised by system locale
+ * @param timestamp - epoch timestamp
+ * @returns {string} formattedDate
+ */
+export const formatLocalDateShort = (timestamp: number): string =>
+    new Intl.DateTimeFormat(
+        undefined, // locales
+        { day: "2-digit", month: "2-digit", year: "2-digit" },
+    ).format(timestamp);