feat: shutdown node after exit from committee

[matthias-wright]

This makes sure that a validator shuts down after being removed from the committee. This also adds a binary that does a e2e test to verify correct behavior.

Changes:

• Adds withdrawal credential for the genesis nodes
• If a validator is removed from the committee (voluntarily or involuntarily), the finalizer will detect it and trigger a coordinated shutdown
• Added a CancellationToken to the application, finalizer, and syncer workers. The workers will await the token in the tokio select loops, and they will also trigger the a cancellation if their Drop implementation.
• Adds a binary for testing the withdrawal and exit flow
  • The binary creates a network of 4 nodes (with reth instances).
  • It will send a withdrawal transaction on behalf of the 4th node that will withdraw the entire stake
  • It will check the balance on reth for the withdrawal credentials (eth address) of node 4 before and after submitting the withdrawal request
  • It will make sure that node 4 was removed from the consensus state

The binary can be executed as follows:

cargo run --release --features prom,e2e --bin withdraw-and-exit -- --log-dir /tmp/rethlogs