New issue labels

[GeorgianaElena]

This adds some extra labels on new issues that use the issue templates:

• needs: triage for bug reports
• needs: discussion for feature requests

This PR also adds a new issue template, for problems that might not be super clear for the contributor if they happen because of a bug, a misconfiguration (and should be on Discourse) or just because of a missing feature.

I'm not sure at all if this is the way to go, but I think it might be a step towards implementing a more effective labeling system, that's sustainable and not based only on the bug-enhancement distinction, as @minrk nicely explained here.

[betatim]

Looks good to me. Let's see if it helps people separate "bug" and "unsure/maybe broken" issues.

I share Min's experience that tagging is super hard to do consistently and once it isn't done rigorously it becomes not useful. I tend to go with "if it is important it will keep coming up" so issues/bugs that aren't on the front page https://github.com/jupyterhub/repo2docker/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc (this is the default view I have for all issues, also use it for PRs) aren't important enough. This means I am +-0 about adding (or not) the new tags.

[choldgraf]

I agree w/ @betatim - I think the question is whether people will reliably remove that tag when an issue no longer needs discussion or triage. If the answer is "yes" then I think this would be useful. But if we suspect that people won't ever touch those tags then I worry it'll be a noisy signal since it won't actually convey any information about the status of the issue. So if we add labels like that I'd want to get some agreement for the team that we'll all start using them, or else the burden will likely fall on one or two people to keep them up to date.

On the extra issue template I am 👍 !