internal/telemetry: revamp

[eliottness]

What does this PR do?

This PR rebuilds fron scratch the current instrumentation telemetry client. More informations here:
https://docs.google.com/document/d/1C3xoTZHQZNQ-Jr1w5mMThIkpHNW_4qKRf-J5CNi7G-k/edit?pli=1&tab=t.0#heading=h.88xvn2cvs9dt

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.

Unsure? Have a question? Request a review!

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-22 18:00:50

Comparing candidate commit bce2138 in PR branch eliott.bouhana/newtelemetry with baseline commit 241a6f1 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 59 metrics, 0 unstable metrics.

[datadog-datadog-prod-us1]

Datadog Report

Branch report: eliott.bouhana/newtelemetry
Commit report: 29cdaf2
Test service: dd-trace-go

❌ 4 Failed (0 Known Flaky), 5225 Passed, 72 Skipped, 2m 27.22s Total Time

❌ Failed Tests (4)

• TestClientEnd2End - gopkg.in/DataDog/dd-trace-go.v1/internal/newtelemetry - Details

  Expand for error

   Failed
   
   === RUN   TestClientEnd2End
   --- FAIL: TestClientEnd2End (0.00s)
       assertions.go:363:
  

• TestClientEnd2End/app-start - gopkg.in/DataDog/dd-trace-go.v1/internal/newtelemetry - Details

  Expand for error

   Failed
   
   === RUN   TestClientEnd2End/app-start
   === PAUSE TestClientEnd2End/app-start
   === CONT  TestClientEnd2End/app-start
       client_test.go:465: 
           	Error Trace:	/home/runner/work/dd-trace-go/dd-trace-go/internal/newtelemetry/client_test.go:465
           	            				/home/runner/work/dd-trace-go/dd-trace-go/internal/newtelemetry/client_test.go:514
           	            				/home/runner/work/dd-trace-go/dd-trace-go/internal/newtelemetry/client_test.go:398
           	            				/opt/hostedtoolcache/go/1.22.11/x64/src/net/http/client.go:259
   ...
  

• TestClientEnd2End/app-start+app-stop - gopkg.in/DataDog/dd-trace-go.v1/internal/newtelemetry - Details

  Expand for error

   Failed
   
   === RUN   TestClientEnd2End/app-start+app-stop
   === PAUSE TestClientEnd2End/app-start+app-stop
   === CONT  TestClientEnd2End/app-start+app-stop
       testing.go:1398: race detected during execution of test
  

• TestClientEnd2End/app-stop - gopkg.in/DataDog/dd-trace-go.v1/internal/newtelemetry - Details

  Expand for error

   Failed
   
   === RUN   TestClientEnd2End/app-stop
   === PAUSE TestClientEnd2End/app-stop
   === CONT  TestClientEnd2End/app-stop
   ==================
   Write at 0x00c00039a480 by goroutine 47:
     gopkg.in/DataDog/dd-trace-go.v1/internal/newtelemetry.TestClientEnd2End.func8()
         /home/runner/work/dd-trace-go/dd-trace-go/internal/newtelemetry/client_test.go:511 +0x204
     testing.tRunner()
   ...