Expose net/http/pprof handlers

[jmunson]

Expose net/http/pprof handlers under /api/debug/pprof/* when the new enablePprofEndpoint (JSON) / enable_pprof_endpoint (YAML) config option is true. The endpoint is disabled by default.

These are useful for adhoc debugging orperformance analysis, or ongoing performance monitoring when polled with Grafana Alloy

Tests have been added to demonstrate the endpoints responding when enabling and not when not enabled - I'm unsure how much value that is adding but wanted to err on the safe side of test coverage, but feel free to drop them if they are superfluous.

Checklist

• allow Maintainers to edit PR (rebase, run coverage, help with tests, ...)
• unit-test added (if change is algorithm)
• functional test added/updated (if change is functional)
• man page updated (if applicable)
• bash completion updated (if applicable)
• documentation updated
• author name in AUTHORS

[jmunson]

Sorry when I wrote this I only ran my own new tests and didn't notice I broke the other tests, so I'm chipping away at those still

[jmunson]

I believe the above timeout is unrelated so I'll leave this as is but let me know if you'd like me to take a deeper look

(edit: triggered it again with a no-op change, seems fine now)

[codecov]

Codecov Report

❌ Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.07%. Comparing base (f59b0d2) to head (953c587).

Files with missing lines	Patch %	Lines
api/router.go	87.50%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1603      +/-   ##
==========================================
- Coverage   77.37%   77.07%   -0.31%     
==========================================
  Files         165      165              
  Lines       15747    15763      +16     
==========================================
- Hits        12185    12150      -35     
- Misses       2356     2410      +54     
+ Partials     1206     1203       -3     

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