feat(plugin): pg-pool plugin implementation

[xiao-lix]

Which problem is this PR solving?

• Closes Request(plugin-postgres): pg-pool #418

Short description of the changes

• Implement plugin-postgres: pg-pool

[codecov-io]

Codecov Report

Merging #501 into master will decrease coverage by 1.77%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #501      +/-   ##
==========================================
- Coverage   90.52%   88.74%   -1.78%     
==========================================
  Files         198      195       -3     
  Lines        9718     9790      +72     
  Branches      882      902      +20     
==========================================
- Hits         8797     8688     -109     
- Misses        921     1102     +181

Impacted Files	Coverage Δ
...es/opentelemetry-exporter-collector/src/version.ts	100% <100%> (ø)	⬆️
packages/opentelemetry-core/src/common/version.ts	100% <100%> (ø)	⬆️
packages/opentelemetry-core/test/utils/url.test.ts	50% <0%> (-50%)	⬇️
...pentelemetry-core/test/internal/validators.test.ts	50% <0%> (-50%)	⬇️
...elemetry-core/test/trace/spancontext-utils.test.ts	55.55% <0%> (-44.45%)	⬇️
...lemetry-core/test/trace/ProbabilitySampler.test.ts	56.52% <0%> (-43.48%)	⬇️
...s/opentelemetry-core/test/trace/NoopTracer.test.ts	60% <0%> (-40%)	⬇️
...s/opentelemetry-core/test/context/B3Format.test.ts	63.39% <0%> (-36.61%)	⬇️
...ges/opentelemetry-core/test/trace/NoopSpan.test.ts	63.63% <0%> (-36.37%)	⬇️
...s/opentelemetry-core/test/trace/tracestate.test.ts	65.06% <0%> (-34.94%)	⬇️
... and 31 more

[markwolff]

Are any of the attributes from pg applicable here?

[xiao-lix]

yes, will fix this.

[markwolff]

For this case, I think this span will be ended immediately -- before the network calls finish. For callbacks scenarios, I think we should patch the callback and end the span (and set the corresponding status) once the callback is called. Similar to pg plugin utils.patchCallback

[mayurkale22]

@open-telemetry/javascript-approvers Please review this one when you get a chance.

[mayurkale22]

@open-telemetry/javascript-approvers: If someone has knowledge of pg-pool (I don't), I'd love another review on this before merging.

[dyladan]

Approving, but added a couple question comments.

[dyladan]

Is this if statement necessary? Is there any case where connect would be missing?

[dyladan]

Do we not support 2.0 versions below 2.0.7?

[mayurkale22]

@xiao-lix Could you please address last round of comments, I think this is good to go.