Faster CI: Optimize APM Parametric Tests

[felixge]

What does this PR do?

1. Speed up "Patch dd-trace-go version" step from 30s to 10s by using a replace directive in go.mod instead of using go get.
2. Split "Run" step into "Build" and "Run" step and by moving away from the legacy parametric/run.sh script.
3. Add "Cache venv" step to speedup build step from ~1m to ~10s
4. Remove "Checkout Go" step that served no apparent purpose.

Together with #2068 this will allow running this pipeline as fast as 3min45s 🚀.

Motivation

See RFC: Faster CI for dd-trace-go 🚀 google doc.

Describe how to test/QA your changes

Reviewer's Checklist

• Changed code has unit tests for its functionality.
• If this interacts with the agent in a new way, a system test has been added.

[pr-commenter]

Benchmarks

Benchmark execution time: 2023-06-26 13:05:56

Comparing candidate commit e19ea10 in PR branch felix.geisendoerfer/fast-ci-faster-parametric-tests with baseline commit ea87357 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 24 metrics, 0 unstable metrics.

[ahmed-mez]

Thank you!