[FEA] GitHub Issue Infrastructure Update

[jarmak-nv]

Describe the solution you'd like
I'd like to (in 2 separate PRs)
1. Replace .md issue templates with .yml forms

• With these templates I'd remove the https://github.com/rapidsai/cudf/labels/%3F%20-%20Needs%20Triage label from always being on new issues

2. Use a GitHub Action to automatically label and reply to issues filed by people outside of RAPIDS
   • Goal: reduce the noise of the https://github.com/rapidsai/cudf/labels/%3F%20-%20Needs%20Triage label and ensure we respond quickly to external filers

Describe alternatives you've considered
We could also do triage rotations with the GHA but I prefer the auto-labeling and leveraging the label to track as needed.

Additional context
We do this in Morpheus - references:

• Form template issues
• Auto Labeler

Looking to solicit feedback prior to making any changes. If feedback is all 🟢 then I'll PR these changes in ASAP and we can work through the specific implementations in the PR review.

[jarmak-nv]

Oh right when I do these PR's I'll also axe:

• https://github.com/rapidsai/cudf/blob/branch-23.08/.github/workflows/add_to_project.yml
• https://github.com/rapidsai/cudf/blob/branch-23.08/.github/workflows/new-issues-to-triage-projects.yml

Projects now have a built-in workflow to add to project, and all classic projects have been closed.

[GregoryKimball]

Hello @jarmak-nv, I noticed this issue while triaging cudf 😂. My process has been to check the ? - Needs Triage flags every week or two and then assign labels, milestones and project status at that time. If we stopped using the ? - Needs Triage label.. I would miss issues like this!

At the same time, I like the idea of giving a special label to externally-filed issues.

[jarmak-nv]

I think I've come around to the feedback on #13542 and will drop the issue template part of it (because there's no ETA on the length fix) and update the GHA to use external as the label.

This way we can have a slack channel that alerts us to any activity on an issue/PR that's labeled external and we don't interrupt existing processes.

[jarmak-nv]

Done - assuming all are happy with the GHA, all it needs is someone with write+ access to the cuDF repo to create an external label.

[vyasr]

@jarmak-nv @GregoryKimball could you comment on whether this issue is still actionable?

[jarmak-nv]

Good question!

Been very away from this for a bit, but I'd be happy to contribute a PR to label external issues if that's something that's still valuable.

The replacing .mds with .ymls has officially been shelved though

[vyasr]

@GregoryKimball WDYT? Do you like the idea of an external label?