Create GitHub Issue Template

[capnramses]

Why

Good descriptions on every GitHub Issue will help as we have a growing number of contributors.
See also #856 for PRs.

What

• Bugs e.g. may be community-reported and require some details, and planned features, should have different templates if possible.
• Why/What/Testing Done Coverage/Risks.
• For bugs some form-filling would be nice e.g.

• Version of Brevitas bug was found in = "x.y.z "
• Expected result = "Halt on completion "
• Observed result = "Caught fire "
• Could you reproduce the buggy behaviour?
• Bug reproduces only sometimes
• Bug reproduces on every run

• "Please provide a screenshot or text copy of the bug"
• Please provide a list of steps/actions that can be taken to reproduce the bug.

[capnramses]

PR opened (linked). I used GH's template creator tool. It didn't seem to pull in my Feature Request template, just the Bug Report one, but I think that's okay to start with (bug report more important for info gathering).