Make Submit function async

[tzdybal]

Currently, our Submit function is async in Rollkit. An option to do that here would be to decouple the inclusion proof generation from the response of the submission.

The flow could be Submit -> get commitment as a response ( can be generated deterministically) and would be an instant response
Then something like getProof(ID) to get the proof which might happen Blocks (minutes) into the future

This would be the current interaction with celestias blob module.

Either way, I think we should merge this and then make changes afterwards , as is does not have to be perfect from the start and we can expect to break the API.

Originally posted by @nashqueue in #1 (comment)