implement partitioned cookies

[bound2]

Solves #4202

• add cookie validation with error logging
• refactor c.SetCookie to accept option pattern modifications as vararg (does not cause issue of breaking change to v1.6.0 is inappropriate #2299)
• refactor c.SetSameSite to use option pattern under the hood

Unsure if slog usage is okay within the project. The cookie doesn't get rejected if it is "invalid" when secure is false but partition is true.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.00%. Comparing base (3dc1cd6) to head (4eecebf).
Report is 96 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4204      +/-   ##
==========================================
- Coverage   99.21%   99.00%   -0.21%     
==========================================
  Files          42       44       +2     
  Lines        3182     3420     +238     
==========================================
+ Hits         3157     3386     +229     
- Misses         17       24       +7     
- Partials        8       10       +2     

Flag	Coverage Δ
	?
--ldflags="-checklinkname=0" -tags "sonic avx"	98.99% <100.00%> (?)
-tags go_json	98.99% <100.00%> (?)
-tags nomsgpack	98.99% <100.00%> (?)
go-1.18	?
go-1.19	?
go-1.20	?
go-1.21	?
go-1.23	99.00% <100.00%> (?)
go-1.24	99.00% <100.00%> (?)
macos-latest	99.00% <100.00%> (-0.21%)	⬇️
ubuntu-latest	99.00% <100.00%> (-0.21%)	⬇️

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