refactor(profiling): extract wall_time.rs file

[morrisonlevi]

Description

PROF-8912

Does two things:

1. Extracts bits from lib.rs and capi.rs and puts them in a new wall_time.rs file.
2. Uses ddog_php_prof_ instead of datadog_profiling_ for functions in wall_time.rs. This function is used by the tracer so it updates ext/engine_hooks.c too.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-01-12 22:04:14

Comparing candidate commit 4f021ef in PR branch levi/wall-time with baseline commit b032b1e in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 41 metrics, 49 unstable metrics.

[realFlowControl]

Whoop Whoop