Pre-release key generation

[jannikluhn]

The public keyper set successfully completed eon DKG, but they don't generate decryption keys yet as not mainnet validators are registered. However, we would like to validate that decryption key generation works and is performant enough. To enable us doing this, we could temporarily disable the proposer check (eg if (proposer_is_registered || local_time < August 10th)) { generate_decryption_key() }). This would make the keypers generate decryption keys, but safely fall back to the protocol-defined rules sometime before the official release. Later, we can remove this condition.

[fredo]

I would prefer an earlier cutoff. Maybe Sunday night.