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 88.52%. Comparing base (55600e6) to head (dfa2d2d).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #61157   +/-   ##
=======================================
  Coverage   88.52%   88.52%           
=======================================
  Files         703      703           
  Lines      208589   208617   +28     
  Branches    40226    40223    -3     
=======================================
+ Hits       184650   184685   +35     
+ Misses      15954    15952    -2     
+ Partials     7985     7980    -5     

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

... and 25 files with indirect coverage changes

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[avivkeller]

Remember to update the docs

[avivkeller]

Other than this is missing a doc entry, LGTM

[LiviaMedeiros]

Agreed, added to the docs.
Initially i intentionally omitted it because these are basically inherited from Uint8Array (we don't document Buffer.prototype.at() whatsoever), but it's worth adding to indicate that these are similar-but-different from Buffer.from(string, encoding).