refactor: improve dark theme, add switch component etc, fix stuff

Co-authored-by: Alex Sparkes <turbomarshmello@gmail.com>

src/App.jsx

@@ -21,26 +21,6 @@ export default class App extends React.PureComponent {
     }
 
     SettingsFunctions.loadSettings();
-    
-    // These lines of code prevent double clicking the page or pressing CTRL + A from highlighting the page
-    document.addEventListener('mousedown', (event) => {
-      if (event.detail > 1) {
-        event.preventDefault();
-      }
-    }, false);
-
-    document.onkeydown = (e) => {
-      e = e || window.event;
-      if (!e.ctrlKey) return;
-      let code = e.which || e.keyCode;
-
-      switch (code) {
-        case 65:
-          e.preventDefault();
-          e.stopPropagation();
-          break;
-      }
-    };
   }
 
   render() {