feat(rpc): Rollup client RPC

[merklefruit]

Both the Hera-exex and the standalone CL will require a spec-compliant RPC module.
From the OP Stack specs and the canonical op-node impl, here are all the RPC methods supported:

• optimism_outputAtBlock returns a 32 byte hash corresponding to the L2 output root
• optimism_safeHeadAtL1Block reference impl
• optimism_version reference impl
• optimism_rollupConfig reference impl
• optimism_syncStatus reference impl

There is also an optional Superchain protocol version endpoint to send events to the L2 execution client
regarding upcoming hard-forks.

The RPC implementation should make use of the Reth RPC crates and types wherever possible to promote good maintainability.

[mahmudsudo]

can i take on this ?