feat(instrumentation-aws-lambda): support ESM handlers and other less common handler patterns

[raphael-theriault-swi]

Which problem is this PR solving?

The Lambda instrumentation doesn't currently support instrumenting ESM handlers, which are now the default, and other less common handler patterns supported by Lambda such as extensionless handler modules and nested handler functions.

Short description of the changes

The previous logic to determine the handler to patch is replaced with an implementation based on the one present in the Lambda runtime. I tried to keep the function names and structure as close to possible to the original to make it easier to cross-reference.

The tests also now use code copied from the Lambda runtime to load handlers, as opposed to just calling require which doesn't properly reflect a real-world scenario and doesn't work at all for ESM.

I also updated the notes about absolute path support in the patching infrastructure. The instrumentation keeps using the same hack but it would probably be a good idea to fix the issue upstream, which is that while absolute paths are taken into account while registering hooks, they are not when matching against the module name within the hook function, which ignores the baseDir.

[codecov]

Codecov Report

Attention: Patch coverage is 97.50000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 90.35%. Comparing base (dfb2dff) to head (6452504).
Report is 171 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2000      +/-   ##
==========================================
- Coverage   90.97%   90.35%   -0.62%     
==========================================
  Files         146      148       +2     
  Lines        7492     7323     -169     
  Branches     1502     1528      +26     
==========================================
- Hits         6816     6617     -199     
- Misses        676      706      +30     

Files	Coverage Δ
...-instrumentation-aws-lambda/src/instrumentation.ts	93.61% <97.22%> (-0.07%)	⬇️
...ry-instrumentation-aws-lambda/src/user-function.ts	97.72% <97.72%> (ø)

... and 58 files with indirect coverage changes

[raphael-theriault-swi]

@JamieDanielson I think you've been pushing a lot for ESM support as a whole, if I rebased this do you think you'd be able to take a look ?