Crate `reth-staged-sync` should be deprecated

[shekhirin]

Describe the feature

The only remaining consumer of reth-staged-sync crate is the CLI, it uses the db initialization helper functions. We can probably move these helpers into the bin/reth itself.

Also, we have the Geth peering test in there, which also needs to be moved somewhere else: https://github.com/paradigmxyz/reth/blob/94d0f3e9edcee6bf825d5b349d889f6ef562d1dd/crates/staged-sync/tests/sync.rs#L19

Additional context

No response