SignedBlindedBeaconBlock SSZ + Benchmark SSZ vs JSON

[metachris]

📝 Summary

• Added SSZ for SignedBlindedBeaconBlock
• Benchmarking SSZ vs JSON encoding and decoding of SignedBlindedBeaconBlock

$ go test -benchmem -run=^$ -bench ^BenchmarkJSONvsSSZEncoding$ github.com/flashbots/go-boost-utils/types

goos: darwin
goarch: arm64
pkg: github.com/flashbots/go-boost-utils/types
BenchmarkJSONvsSSZEncoding/Encode_JSON-10         	   18561	     62939 ns/op	   50754 B/op	     274 allocs/op
BenchmarkJSONvsSSZEncoding/Encode_SSZ-10          	  855457	      1368 ns/op	    9472 B/op	       1 allocs/op
BenchmarkJSONvsSSZEncoding/Decode_JSON-10         	    7621	    153292 ns/op	   30433 B/op	     613 allocs/op
BenchmarkJSONvsSSZEncoding/Decode_SSZ-10          	  276904	      3968 ns/op	   10116 B/op	     152 allocs/op

Looks like SSZ encoding/decoding is about 40-50x faster.

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✅ I have run these commands

• make lint
• make test
• go mod tidy

[jtraglia]

LGTM. Quite the difference in performance.