Adding a feature request issue template

Using an issue template is always a good practice when we try to submit an issue.
Signed-off-by: rick <rick@jenkins-zh.cn>

.github/ISSUE_TEMPLATE/feature_request.md

+---
+name: Feature Request
+about: Have a good idea? Please don't hesitate to write it down, describe the new feature.
+---
+
+<!--
+You don't need to remove this comment section, it's invisible on the issues page.
+
+## General remarks
+
+* Attention, please fill out this issues form using English only!
+* 注意！GitHub Issue 仅支持英文，中文 Issue 请在 [论坛](https://kubesphere.com.cn/forum/) 提交。
+* This form is to report bugs. For general usage questions you can join our Slack channel
+       [KubeSphere-users](https://join.slack.com/t/kubesphere/shared_invite/enQtNTE3MDIxNzUxNzQ0LTZkNTdkYWNiYTVkMTM5ZThhODY1MjAyZmVlYWEwZmQ3ODQ1NmM1MGVkNWEzZTRhNzk0MzM5MmY4NDc3ZWVhMjE)
+-->
+
+**What's it about?**
+<!--
+A clear and concise description of what this feature request is.
+-->
+
+**What's the reason why we need it?**
+<!--
+Please tell us if you think it's a necessary feature for Kubesphere. Give us as many details about it as you can. 
+Two or more use cases might be very helpful when other contributors try to go through this request. If you has some references,
+please just add it below.
+-->
+
+I believe this is an important feature for Kubesphere. There're a few use cases:
+
+* case one
+* case two
+* ...
+
+Please leave your comments below if there's anyone agree with me. Or just give me a thumb up.
+
+**Area Suggestion**
+<!--
+In order to have a clear issue list, giving an accuracy area is necessary. If you are not sure about it, please just leave it alone.
+
+You can find some possible areas below. Please attention, sometimes crossing multiple areas might be possible. So, you 
+can keep one or more areas in this issue.
+
+/area alerting
+/area api
+/area apiserver
+/area app-management
+/area audit
+/area console
+/area devops
+/area documentation
+/area edge
+/area iam
+/area installation
+/area logging
+/area microservice
+/area monitoring
+/area multicluster
+/area networking
+/area notification
+/area observability
+/area performance
+/area security
+/area storage
+/area test
+/area upgrade
+-->
+
+/kind feature-request