Newtype wrappers for various block numbers / block height

[sveitser]

We recently had several occurrences where block number were confused. Some were discovered in PR reviews, some only after merge to main. I was previously of the opinion that this isn't so important because we strive to maintain sufficient test coverage but I have changed my mind. If we're rushing to ship things and skip writing tests then having more help from the compiler on such mistakes would save us a lot of time debugging.

So I think we should add newtypes for at least hotshot block height, L1 head block number, L1 finalized block number.