chore(issues): simplify Good First Issue template

[BrendenChouinard]

Description

Please explain the changes you made, including a reference to the related issue if applicable

What changed:

• Short YAML issue form with required: summary, context, acceptance criteria
• Auto-labels: good first issue, help wanted

Why:

• Reduced friction for new contributors while keeping info consistent.

Validation:

• YAML renders via GitHub Issue Forms
• Labels apply on issue creation
• Field set aligns with contributing and CoC

Links:

• Closes Simplify good-first-issue template #1922
• GitHub Issue Forms docs (syntax & placement)

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[github-actions]

This PR is stale because it has been open for 45 days with no activity. Please tag a maintainer for help on completing this PR, or close it if you think it has become obsolete.

[EzraBrooks]

Big fan of migrating to YAML issue forms. could you remove the existing markdown template? then I'll approve and merge this.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.22%. Comparing base (50a0edd) to head (599d876).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3584      +/-   ##
==========================================
+ Coverage   46.16%   46.22%   +0.06%     
==========================================
  Files         720      720              
  Lines       59180    59176       -4     
  Branches     7594     7596       +2     
==========================================
+ Hits        27317    27350      +33     
+ Misses      31696    31660      -36     
+ Partials      167      166       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[nbbrooks]

There is a lot of info for a first time contributor in the md file that is not carried over, but some of it is outdated (https://answers.ros.org/questions/) and some of it I think is of questionable value.

Based on future Qs we get we can update this template, https://moveit.ai/documentation/contributing/ etc