Add assertions to sim tests

[dapplion]

• From Sim tests overhaul #4275

Sim tests are a crucial tool for our CI pipeline, but currently lack of assertions to detect bugs. Currently tests only assert that:

• Finality / Justification is reached within N epochs

Proposed assertions

Assertion on epoch:

• Attester participation rates a minimum threshold: Assert with debug states route
• Sync committee participation rates a minimum threshold: Assert with following beacon blocks
• All blocks in epoch are proposed: Assert with debug state route
• Blocks received by all nodes with max threshold: ?? How to assert?
• Gossip scores of all peers at a minimum value: Prysm, Lighthouse, and Lodestar expose peer scores via custom API routes
• Correct voting of a majority vote of eth1_data

Run modes / actions to perform

• Run to finalization + N epochs
• Validator exit: Assert inclusion with blocks, effect with validator status route
• Validator proposer slashing: Assert inclusion with blocks, effect with validator status route
• Validator attester slashing: Assert inclusion with blocks, effect with validator status route
• Process deposits from eth1 contract: Assert inclusion with blocks, effect with validator status route
• Go through forks: Other assertions cover healthy transition
• Finalized sync: Assert reaching head within some time limit
• Unknown block sync: ?? Not sure how to trigger
• Lightclient sync + follow head: Light-client should be managed programatically against a node run in another process. Assert syncs to head + follows the head in time

Background

To get started, Prysm has done an excellent job on this field so we should base our work on theirs.

• Prysm's e2e infra is documented here: https://docs.prylabs.network/docs/devtools/end-to-end/
• Assertions source code: https://github.com/prysmaticlabs/prysm/blob/develop/testing/endtoend/evaluators/operations.go