Verify minimum peer staking

[helins]

The minimum stake is currently set to 1e9 CVX.

Before this requirement, I was already noticing situations where finality was 10 - 20x slower when at least some peers where fairly low staked.

Using Convex 0.7.11 with a local network of 5 peers:

• Staked equally with 1e9 CVX, slow finality
• Staked equally with 1e9 + 1 CVX, fast finality
• At least 2 staked at 1e9 + 1, rest at 1e9, fast finality with occasional degradation
• Different combinations, some being staked even below 1e9, weirdly behaves a bit better than the last one

Where fast finality is below 100 ms.

Recommendations:

• Forbid setting stake below the minimum in set-peer-stake
• Ensure the minimum is enforced whenever relevant
• Ensure stakes are computed right during consensus, behaviour looks a bit odd overall