Introducing the support forum

[kpcyrd]

I'm going to close some tracking issues and replace them with github discussions. You are very welcome to ask for support by starting a new discussion. The intended usage is:

• General - General discussion that doesn't match any of the other categories goes here.
• Ideas - Ideas can be collected and discussed here before they're moved to an actionable task in the issue tracker.
• Q&A - If you have a specific question/problem that you'd like to solve please post it there. Don't be shy, asking questions helps other users too that might have the same question.
• Show and tell - If you're running a public rebuilder you're welcome to post it there in a new thread.