Revert "add navigator script"

This reverts commit 61c27e930e.

public/javascript/navigator.js

@@ -1,27 +0,0 @@
-(function chapterNavigation() {
-  document.addEventListener('keydown', function (e) {
-    if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) {
-      return;
-    }
-    if (window.search && window.search.hasFocus()) {
-      return;
-    }
-
-    switch (e.key) {
-      case 'ArrowRight':
-        e.preventDefault();
-        var nextButton = document.querySelector('a[rel="next"]');
-        if (nextButton) {
-          window.location.href = nextButton.href;
-        }
-        break;
-      case 'ArrowLeft':
-        e.preventDefault();
-        var previousButton = document.querySelector('a[rel="prev"]');
-        if (previousButton) {
-          window.location.href = previousButton.href;
-        }
-        break;
-    }
-  });
-})();