Darcy.rayner/step function support poc

[DarcyRaynerDD]

What does this PR do?

Adds support to detect step function events, and inject relevant metadata into X-Ray and Datadog traces

Motivation

Testing Guidelines

Additional Notes

[codecov-io]

Codecov Report

Merging #29 into master will increase coverage by 0.28%.
The diff coverage is 91.66%.

@@            Coverage Diff             @@
##           master      #29      +/-   ##
==========================================
+ Coverage    89.8%   90.09%   +0.28%     
==========================================
  Files          21       21              
  Lines         510      555      +45     
  Branches       76       88      +12     
==========================================
+ Hits          458      500      +42     
- Misses         32       34       +2     
- Partials       20       21       +1

Impacted Files	Coverage Δ
src/trace/constants.ts	100% <100%> (ø)	⬆️
src/trace/trace-context-service.ts	81.81% <50%> (-3.9%)	⬇️
src/trace/listener.ts	87.09% <50%> (-5.77%)	⬇️
src/trace/context.ts	97.32% <97.56%> (+1.48%)	⬆️

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[swfunc]

LGTM