Added a CodeQL workflow to check for bugs through code analysis. Fixed numerous bugs and implemented safeguards as already reported.

src/web/html/index.html

@@ -153,7 +153,7 @@
                         <script type="text/javascript">
                             // Must be text/javascript rather than application/javascript otherwise IE won't recognise it...
                             if (navigator.userAgent && navigator.userAgent.match(/Trident/)) {
-                                document.write("Internet Explorer is not supported, please use Firefox or Chrome instead");
+                                document.getElementById("notice").innerHTML += "Internet Explorer is not supported, please use Firefox or Chrome instead";
                                 alert("Internet Explorer is not supported, please use Firefox or Chrome instead");
                             }
                         </script>