Koenig - Fixed jump-to-top bug when focusing editor

refs https://github.com/TryGhost/Ghost/issues/9311
- the editor was being focused and the cursor placed properly but the act of focusing also reset the scroll position
- pulled the `.gh-koenig-editor` class into the component rather than leaving it in the template so that the component has access to `this.element`
- ensure the `.gh-koenig-editor` container is scrolled all the way to the bottom after focusing the editor

ghost/admin/app/components/gh-koenig-editor.js

@@ -3,7 +3,7 @@ import Component from '@ember/component';
 export default Component.extend({
 
     // public attrs
-    tagName: '',
+    classNames: ['gh-koenig-editor'],
     title: '',
     titlePlaceholder: '',
     body: null,
@@ -35,6 +35,9 @@ export default Component.extend({
                 this._editor.run((postEditor) => {
                     postEditor.setRange(range.tail.section.tailPosition());
                 });
+
+                // ensure we're scrolled to the bottom
+                this.element.scrollTop = this.element.scrollHeight;
             }
         },
 

ghost/admin/app/templates/components/gh-koenig-editor.hbs

@@ -1,5 +1,3 @@
-{{!-- scrollable container --}}
-<div class="gh-koenig-editor">
 {{!-- full height content pane --}}
 <div class="gh-koenig-editor-pane" onclick={{action "focusEditor"}}>
     {{gh-textarea title
@@ -22,4 +20,3 @@
         didCreateEditor=(action "onEditorCreated")
     }}
 </div>
-</div>