awaitTxAssured

[euonymos]

User's actions that produce transaction might be presented to user based on the transaction status:

• signed (submitted)
• verified (included in the block)
• assured (there are enough blocks on top on the tx's block so we can be sure is won't be rolled back)

CTL provides awaitTxConfirmed* functions to handle verified status but currently has no means for the "assured", which might be added to hydra-auction-offchain.

To save up the amount of queries to the back-end, the block height might be included in awaitTxConfirmed Promise, and similar function awaitTxAssured might accept it to avoid figuring out tx's block.