Setup bug/feature contribution dialog on Github

[roll]

Overview

See nice examples on Github like https://github.com/withastro/starlight/issues (click "New Issue"). We also can consider separating issues (actionable) and feature requests / ideas / questions (discussable and votable) like they do

[peterdesmet]

I think this can be setup with https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository