[#285] Add option of KeyAddress transaction with VUnit parameter

Description

Problem: Transfer logic is the same for ContractAddress and KeyAddress, though it should be different

Solution: Add slightly different logic to transfer in case destination hash is KeyAddress. In case of KeyAddress hash transfer requires parameter to be ValueUnit and falls with error in other cases. Issue still requires better error message and codes duplicates to be removed

Related issue(s)

Resolves (except for tests) #285 (closed)

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