adr: preconfs (or something like it)

We will have a long block time (>1min), at least for a while. This creates a problem for submitting transactions, as we don't want to block for >1min.

The prover will have to maintain some intermediate state that allows multiple transactions to be submitted, without the inclusion dependency of the previously submitted intermediate transactions. Until then, the prover will not run full state validation on incoming transactions, and submission is optimistic.

This issue will require an ADR for deciding how we want to handle this