Support hotkey chapters like mpv

[enter-a-random-username]

Easy way to change chapters, go back or forwards.

diff --git a/src/scripts/keyboardNavigation.js b/src/scripts/keyboardNavigation.js
index dedea77d7..dedea77d5 100644
--- a/src/scripts/keyboardNavigation.js
+++ b/src/scripts/keyboardNavigation.js
@@ -43,7 +43,7 @@ const KeyNames = {
 /**
  * Keys used for keyboard navigation.
  */
-const NavigationKeys = ['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown'];
+const NavigationKeys = ['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'PageUp', 'PageDown'];
 
 /**
  * Elements for which navigation should be constrained.
@@ -140,6 +140,13 @@ export function enable() {
                 inputManager.handleCommand('down');
                 break;
 
+            case 'PageUp':
+                inputManager.handleCommand('nextchapter');
+                break;
+            case 'PageDown':
+                inputManager.handleCommand('previouschapter');
+                break;
+
             case 'Back':
                 inputManager.handleCommand('back');
                 break;

In general more hotkeys would be nice. Maybe even a mapping option for common controls from the player.