Investigate scenario of a single giant subnet

[shotasilagadze]

While investigating alpha getting bigger, we will eventually reach a point where there is gonna be a single giant subnet (alpha=64). It would be very useful to understand more what happens there. In that case, we won't need any aggregation at all, since all the attestations will go directly into the global topic.

Hence, we don't need any aggregation signatures or proofs (so attestation size is smaller) and we won't have any aggregator redundancy (we now have 16x redundancy because of aggregators). It would be nice to have some vision on how things would look like in that regime (for different number of validators), as it seems like a possible future with Orbit.