Performance improvements

[eminano]

This PR updates the json library to improve performance of encoding during the hot path. The changes are a drop in replacement using the sonic library.

It also updates the method to retrieve the table column in the translator to avoid the memory allocation.

goos: darwin
goarch: arm64
pkg: github.com/xataio/pgstream/pkg/schemalog
cpu: Apple M2
Benchmark_GetColumnByName-8        	10212780	       125.7 ns/op	     320 B/op	       4 allocs/op
Benchmark_GetColumnByNameNoPtr-8   	98911633	        12.06 ns/op	       0 B/op	       0 allocs/op

Relates to https://github.com/xataio/xata/pull/5004, where benchmarks were performed under load comparing go-json and sonic libraries:

• Use go-json library

  • Reduction of ~35% cpu and ~28% memory allocations

• Use sonic library

  • Reduction of ~30% cpu and ~42% memory allocations