chore: add extension-definitions.yaml (#134)

添加扩展定义描述文件，以便后续在 Halo 中展示或者启用具体的扩展点。 /kind feature ```release-note 添加扩展定义描述文件，以便后续在 Halo 中展示或者启用具体的扩展点。 ```
halo-dev · Jun 25, 2024 · 944bf37 · 944bf37
1 parent 40de277
commit 944bf37
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/src/main/resources/extensions/extension-definitions.yaml b/src/main/resources/extensions/extension-definitions.yaml
@@ -0,0 +1,9 @@
+apiVersion: plugin.halo.run/v1alpha1
+kind: ExtensionDefinition
+metadata:
+  name: default-comment-widget
+spec:
+  className: run.halo.comment.widget.DefaultCommentWidget
+  extensionPointName: comment-widget
+  displayName: "默认评论组件"
+  description: "Halo 默认提供的评论组件插件"