Add licensing info to the bottom of the page

Author: DerpyChap

index.css

@@ -6,6 +6,11 @@ body {
   align-items: center;
 }
 
+.footer {
+  text-align: center;
+  font-size: small;
+}
+
 h1, h2, h3 {
   text-align: center;
 }

index.html

@@ -308,6 +308,15 @@ <h2>Version history</h2>
       Initial release
     </p>
   </div>
+  <div class="footer">
+    <p>
+      <a href="https://github.com/TC-Chart-Converter/TC-Chart-Converter.github.io/">Trombone Champ Chart Converter</a> by RShields and contributors<br>
+      Licensed under the <a href="https://github.com/TC-Chart-Converter/TC-Chart-Converter.github.io/blob/main/LICENSE">GNU Affero General Public License v3.0</a><br>
+      <br>
+      <a href="https://github.com/colxi/midi-parser-js">MidiParser.js</a> by Sergi Guzman and contributors<br>
+      Licensed under the <a href="https://github.com/colxi/midi-parser-js/blob/master/LICENSE">GNU General Public License v3.0</a>
+    </p>
+  </div>
 </div>
 <script>Init.init()</script>
 </body>