Create CODE_OF_CONDUCT.md

[jennaswa]

• adds a CoC to match MDAnalysis's current CoC
• includes a link to NumFOCUS's new reporting form

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.03%. Comparing base (5983c10) to head (633af86).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #174   +/-   ##
=======================================
  Coverage   90.03%   90.03%           
=======================================
  Files           6        6           
  Lines         953      953           
  Branches      126      126           
=======================================
  Hits          858      858           
  Misses         58       58           
  Partials       37       37           

☔ View full report in Codecov by Harness.
📢 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.

[read-the-docs-community]

Documentation build overview

📚 GridDataFormats | 🛠️ Build #33291764 | 📁 Comparing 633af86 against latest (5983c10)

  🔍 Preview build  

2 files changed

± index.html
± gridData/core.html

[orbeckst]

Thanks for adding! Lgtm