[pallet-revive] eth-rpc minor fixes

[pgherveou]

• Add option to specify database_url using DATABASE_URL environment variable
• Add a eth-rpc-tester rust bin that can be used to test deployment before releasing eth-rpc
• make evm_block non fallible so that it can return an Ok response for older blocks when the runtime API is not available
• update cargo.lock to integrate changes from fix: don't wrap rpc error in DisconnectedWillReconnect in reconnecting rpc client subxt#1904

[pgherveou]

/cmd prdoc --audience runtime_dev --bump minor

[paritytech-workflow-stopper]

All GitHub workflows were cancelled due to failure one of the required jobs.
Failed workflow url: https://github.com/paritytech/polkadot-sdk/actions/runs/12952544627
Failed job name: cargo-clippy