feat: add health check to public directory

[jsnwesson]

This PR adds a health endpoint to the Learner Record that returns a JSON object.

To test locally:

• pull down branch
• run npm run start
• go to localhost:1990/health, which will send a JSON object file.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.01%. Comparing base (5f3585f) to head (d86efa0).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #490   +/-   ##
=======================================
  Coverage   74.01%   74.01%           
=======================================
  Files          28       28           
  Lines         431      431           
  Branches      100      100           
=======================================
  Hits          319      319           
  Misses        111      111           
  Partials        1        1           

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