buffer: add Buffer.fromHex() and Buffer.fromBase64()

[LiviaMedeiros]

These methods are already present on Uint8Array, so without defining them on Buffer they return instances of Uint8Array. This introduces wrapper to return instances of Buffer instead.

Fixes: #61146

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.54%. Comparing base (55600e6) to head (c2f669d).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61157      +/-   ##
==========================================
+ Coverage   88.52%   88.54%   +0.02%     
==========================================
  Files         703      703              
  Lines      208589   208617      +28     
  Branches    40226    40223       -3     
==========================================
+ Hits       184650   184721      +71     
+ Misses      15954    15919      -35     
+ Partials     7985     7977       -8     

Files with missing lines	Coverage Δ
lib/buffer.js	100.00% <100.00%> (ø)

... and 45 files with indirect coverage changes

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