[pallet-revive] Eth RPC integration

[pgherveou]

This PR introduces the necessary changes to pallet-revive for integrating with our Ethereum JSON-RPC.

Related PR: paritytech/revive-ethereum-rpc#5

Changes Included:

• A new pallet::call Call::eth_transact. This is used as a wrapper to accept unsigned Ethereum transaction, valid call will be routed to Call::call or Call::instantiate_with_code

• A custom UncheckedExtrinsic struct, that wraps the generic one usually and add the ability to check eth_transact calls sent from an Ethereum JSON-RPC proxy.

• Generated types and traits to support implementing a JSON-RPC Ethereum proxy.

Flow Overview:

• A user submits a transaction via MetaMask or another Ethereum-compatible wallet.
• The proxy dry run the transaction and add metadata to the call (gas limit in Weight, storage deposit limit, and length of bytecode and constructor input for contract instantiation)
• The raw transaction, along with the additional metadata, is submitted to the node as an unsigned extrinsic.
• On the runtime, our custom UncheckedExtrinsic define a custom Checkable implementation that converts the unsigned extrinsics into checked one
• It recovers the signer
• validates the payload, and injects signed extensions, allowing the system to increment the nonce and charge the appropriate fees.
• re-route the call to pallet-revive::Call::call or pallet-revive::Call::instantiateWithCode

[pgherveou]

The code used to generate rpc_types_gen.rs and rpc_methods_gen.rs will be added in a separate PR to keep the diff manageable here