DOC: Add README.md

[aresnow1]

What do these changes do?

Add README.md.

Related issue number

Fixes #xxxx

Check code requirements

• [ ] tests added / passed (if needed)
• [ ] Ensure all linting tests pass

[codecov[bot]]

Codecov Report

Merging #24 (d3f4da9) into main (d4ace47) will decrease coverage by 0.66%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #24      +/-   ##
==========================================
- Coverage   91.30%   90.64%   -0.66%     
==========================================
  Files          42       42              
  Lines        3187     3187              
  Branches      638      638              
==========================================
- Hits         2910     2889      -21     
- Misses        204      218      +14     
- Partials       73       80       +7     

Flag	Coverage Δ
unittests	90.55% <ø> (-0.60%)	:arrow_down:

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see 5 files with indirect coverage changes