Add account based filtering of the schedule

Implement personal filtering of the schedule based on events marked as
being interested in and filtering based on assigned crew for events.

utils/functions.ts

@@ -0,0 +1,9 @@
+import type { LocationQueryValue } from 'vue-router';
+
+export function queryToString(item?: null | LocationQueryValue | LocationQueryValue[]) {
+	if (item === null)
+		return "";
+	if (item instanceof Array)
+		return queryToString(item[0])
+	return item;
+}