add AWS X-Ray Lambda propagator

[martinkuba]

Which problem is this PR solving?

Fixes part of #4494

This is a new propagator based on this AWS Lambda spec.

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.80%. Comparing base (2610122) to head (d61116f).
Report is 16 commits behind head on main.

❗ Current head d61116f differs from pull request most recent head 12b1e23. Consider uploading reports for the commit 12b1e23 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4554      +/-   ##
==========================================
+ Coverage   90.77%   92.80%   +2.03%     
==========================================
  Files          90      328     +238     
  Lines        1930     9512    +7582     
  Branches      417     2047    +1630     
==========================================
+ Hits         1752     8828    +7076     
- Misses        178      684     +506     

see 244 files with indirect coverage changes

[pichlermarc]

@martinkuba we can remove experimental/packages/propagator-aws-xray-lambda/CHANGELOG.md as there's shared changelog in this repo.

[pichlermarc]

Generally looks good 👍

Blocking the PR via Request changes until #4599 or #4603 is merged to avoid introducing a dependency on contrib

XRay propagator was merged, no more reasons to block this PR.

[pichlermarc]

A few more comments, overall looks good 👍