docs: add doc on development the library

[powersj]

Basic document on how to do development of the library itself.

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• pytest tests completes successfully
• Commit messages are conventional
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #479 (1c0bcfd) into master (c06cb78) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #479   +/-   ##
=======================================
  Coverage   89.42%   89.42%           
=======================================
  Files          39       39           
  Lines        3347     3347           
=======================================
  Hits         2993     2993           
  Misses        354      354           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c06cb78...1c0bcfd. Read the comment docs.

[bednar]

Thanks for your PR 👍

LGTM 🚀