Add serialization method for StateSignatureTransaction in hedera.app

[IvanKavaldzhiev]

Problem

Since the platform will pass all transaction types as Bytes, the StateSignatureTransactions which the platform creates itself should have a way to be serialized by a specific logic from the consumer of these transactions (in this case hedera.app). This method will be invoked by the platform to get its StateSignatureTransactions serialized to Bytes and then send them back to hedera.app as Bytes inside a ConsensusEvent. The consumer knows what type it uses as a container for these Bytes and can easily deserialize them back to the proper wrapper type.

Solution

Enhance hedera.app with a static method that gets StateSignatureTransaction pbj type as an input, puts it into a new Transaction and returns its serialization form as Bytes pbj type. The exact business logic of the serialization from StateSignatureTransaction to Bytes should be hidden from the platform and be visible only for hedera.app.

Alternatives

No response