feat: link discussion board for issue creation

创建 issue 时将显示指向 discussion 的链接，并不再显示空 issue 模板，以建议社区使用 issue 模板

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Feature Request | 特性请求
+    url: https://github.com/linuxdeepin/developer-center/discussions/new?category=features-request-ideas-%E7%89%B9%E6%80%A7%E8%AF%B7%E6%B1%82-%E5%A4%B4%E8%84%91%E9%A3%8E%E6%9A%B4
+    about: Please create feature requests to the discussion board in our developer-center repo.
+  - name: General Discussion & Questions | 常规讨论与问答
+    url: https://github.com/linuxdeepin/developer-center/discussions/categories/q-a-%E9%97%AE%E7%AD%94%E6%9D%BF%E5%9D%97
+    about: Please use the discussion board in our developer-center repo.