Create question issue template

Author: Zerpet

Diff for: .github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,12 @@
+---
+name: Question
+about: Guidance to submit questions
+title: ''
+labels: question
+assignees: ''
+
+---
+
+**For questions**, please start a discussion in [RabbitMQ Discussions](https://github.com/rabbitmq/rabbitmq-server/discussions)
+or send an email to [RabbitMQ Mailing list](https://groups.google.com/g/rabbitmq-users), stating that your question is regarding
+RabbitMQ Cluster Operator.