feat: add snmalloc support

[Rjected]

This enables optional snmalloc support. I have not benchmarked our performance with snmalloc yet. This is implemented by adding a snmalloc feature to reth-cli-util and the reth bin, like we do with the jemalloc feature.

Instead of making these mutually exclusive features that would compile error if both are enabled, we just add a preference for jemalloc in the reth-cli-util crate. This also introduces snmalloc-native, which passes down snmalloc's native-cpu feature. This preference is explicitly documented in reth-cli-util.

[gakonst]

@hai-rise any thoughts? I know you guys like that allocator