[FR] - Add possibilit to adding actual datums for provided reference inputs when building a transaction.

[carbolymer]

Describe the feature you'd like
When building a transaction, which uses reference inputs with datum hashes, it may be useful for an user to be able to provide an actual datum, which could be then made available for the plutus script.

For this purpose a new flag, which will accept a datum value, needs to be added to transaction building commands.

This was implemented in cardano-api in IntersectMBO/cardano-api#803