Add era import command for CLI

[mattsse]

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Describe the feature

with https://github.com/paradigmxyz/reth/pull/15737

we can now import era files into the db

for compat with other clients we need to add a CLI command that does this, see also:

https://github.com/ethereum/go-ethereum/blob/14f15430bb99646f516e239271f21e4a52584666/cmd/geth/chaincmd.go#L413-L413

ref:

https://github.com/paradigmxyz/reth/blob/ee8d7d00cb07ee7d344e708c74be7a18636587e4/bin/reth/src/cli/mod.rs#L211-L211

Additional context

No response