Refactored realtime API. Add dot component and colored dots in log.

components/common/Dot.js

@@ -0,0 +1,15 @@
+import React from 'react';
+import classNames from 'classnames';
+import styles from './Dot.module.css';
+
+export default function Dot({ color, size, className }) {
+  return (
+    <div
+      style={{ background: color }}
+      className={classNames(styles.dot, className, {
+        [styles.small]: size === 'small',
+        [styles.large]: size === 'large',
+      })}
+    />
+  );
+}