[Editor] Move the keyboard manager at the container level

- This way, the keyboard callbacks are called even if the page has not
the focus, hence the user doesn't have to guess that they have to click
on the page which is a bit painful especially in Ink mode.
- Add two keyboard shortcuts to commit a Freetext editor (ctrl+enter and
escape).

web/base_viewer.js

@@ -734,6 +734,7 @@ class BaseViewer {
             });
 
             this.#annotationEditorUIManager = new AnnotationEditorUIManager(
+              this.container,
               this.eventBus
             );
             if (mode !== AnnotationEditorType.NONE) {