Default MaxHeaderSize to 4kb

[avalonche]

📝 Summary

Add flag for boost to configure max header size, defaulting to 4kb.

⛱ Motivation and Context

This is to prevent DoS attacks by preventing attackers sending oversized headers to mev-boost.

📚 References

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✅ I have run these commands

• make lint
• make test
• make run-mergemock-integration
• go mod tidy

[codecov-commenter]

Codecov Report

Merging #206 (ada08fc) into main (f714167) will increase coverage by 0.45%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##             main     #206      +/-   ##
==========================================
+ Coverage   71.65%   72.11%   +0.45%     
==========================================
  Files           6        6              
  Lines         621      624       +3     
==========================================
+ Hits          445      450       +5     
+ Misses        149      148       -1     
+ Partials       27       26       -1     

Flag	Coverage Δ
unittests	72.11% <85.71%> (+0.45%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cmd/mev-boost/main.go	4.81% <0.00%> (-0.06%)	⬇️
server/service.go	82.50% <100.00%> (+1.11%)	⬆️

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[metachris]

Please remove the cli flag for it, I'd prefer not accumulating Flags for every setting. If we want to make it configurable then we can start with only an env var, but i don't expect this to change much.

Should be fine to just define a constant for now, maybe with am env var override.

[metachris]

thanks 👍