Initialize e2e tests

[karen-sarkisyan]

Important: This is a draft PR to show a somewhat working setup for e2e tests. I will rewrite it more or less entirely. It has only one actual test to check if setup process works.

Changes in Helios itself that were necessary:

1. Don't hardcode seconds_per_slot value (12) for ethereum
2. When finality update is not available, use optimistic update without panicking. Helios wouldn't sync otherwise for at least 2 epochs, i.e about 30 minutes
3. Trust genesis block when checking finality proof
4. Add --config-path CLI argument to pass a temporary config file with testnet's parameters

Also the setup is currently:

• only for Ethereum
• only in CLI mode, no WASM

Prerequisites

1. Have docker running
2. Installed Kurtosis CLI.

Running tests (only 1) to check if harness works

Use command

cargo test --package helios-e2e-tests ethereum::test_chain_id -- --nocapture