perf(db): reduce allocations in Compact derive

[DaniPopes]

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Closes https://github.com/paradigmxyz/reth/issues/11296

Moved fields encoding and flag construction to inner method, then wrapped it with either tmp buffer for zstd, or pass on the buffer directly to it if no zstd

WIP: use compress_to_buffer which requires another compat struct between zstd trait and bufmut

Blocked by https://github.com/paradigmxyz/reth/issues/11351

cc @joshieDo