Added timezone and default date range settings.

components/settings/TimezoneSetting.js

@@ -0,0 +1,31 @@
+import React from 'react';
+import { FormattedMessage } from 'react-intl';
+import { listTimeZones } from 'timezone-support';
+import DropDown from '../common/DropDown';
+import Button from '../common/Button';
+import useTimezone from 'hooks/useTimezone';
+import { getTimezone } from 'lib/date';
+import styles from './TimezoneSetting.module.css';
+
+export default function TimezoneSetting() {
+  const [timezone, saveTimezone] = useTimezone();
+  const options = listTimeZones().map(n => ({ label: n, value: n }));
+
+  function handleReset() {
+    saveTimezone(getTimezone());
+  }
+
+  return (
+    <>
+      <DropDown
+        menuClassName={styles.menu}
+        value={timezone}
+        options={options}
+        onChange={saveTimezone}
+      />
+      <Button className={styles.button} size="small" onClick={handleReset}>
+        <FormattedMessage id="button.reset" defaultMessage="Reset" />
+      </Button>
+    </>
+  );
+}