http: add http.setGlobalProxyFromEnv()

[joyeecheung]

This adds an API to dynamically enable built-in proxy support for all of fetch() and http.request()/https.request(), so that users do not have to be aware of them all and configure them one by one.

[nodejs-github-bot]

Review requested:

• @nodejs/crypto
• @nodejs/http
• @nodejs/net

[codecov]

Codecov Report

❌ Patch coverage is 93.02326% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.51%. Comparing base (644fb88) to head (cc30706).
⚠️ Report is 27 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/http.js	94.82%	3 Missing ⚠️
lib/internal/http.js	87.50%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60953      +/-   ##
==========================================
- Coverage   88.51%   88.51%   -0.01%     
==========================================
  Files         703      703              
  Lines      208394   208482      +88     
  Branches    40193    40209      +16     
==========================================
+ Hits       184470   184529      +59     
- Misses      15934    15952      +18     
- Partials     7990     8001      +11     

Files with missing lines	Coverage Δ
lib/_http_agent.js	97.30% <100.00%> (-0.02%)	⬇️
lib/https.js	98.22% <100.00%> (-0.02%)	⬇️
lib/http.js	98.82% <94.82%> (-1.18%)	⬇️
lib/internal/http.js	92.11% <87.50%> (-3.66%)	⬇️

... and 48 files with indirect coverage changes

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