Add custom healthcheck path

[akuma12]

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs? - I would if I knew where to do that.
• Did you write any new necessary tests?

What does this PR do?

Fixes #341 by adding a healthcheck_path property to the LitServer class, defaulting to the current path of /health.

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in GitHub issues there's a high chance it will not be merged.

Did you have fun?

I did!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96%. Comparing base (e23469c) to head (14077f2).
Report is 1 commits behind head on main.

Additional details and impacted files

@@         Coverage Diff         @@
##           main   #342   +/-   ##
===================================
  Coverage    96%    96%           
===================================
  Files        22     22           
  Lines      1408   1411    +3     
===================================
+ Hits       1345   1348    +3     
  Misses       63     63           

[aniketmaurya]

Thanks for your patience @akuma12! This looks great 🚀