Add functions for remove/remove all signatures

[jbair06]

Problem

Issued copied from JS SDK: hashgraph/hedera-sdk-js#2491

Once a signature has been added via addSignature, there is no convenience method to remove the signature.

Removing signatures is helpful when a transaction has a signing account that has a large keylist with many thresholds. If all signatures added to the transaction result in a transaction too large to submit, then only the minimum number of signatures required to make the transaction valid should be added to the transaction.

Also, if a signature is added, the owner of the key might decide to revoke the signature. Without recreating the transaction and re adding all the signatures, this is not possible.

Solution

• Add removeSignature(publicKey/signature) method
• Add removeAllSignatures() method

These two convenience methods will be helpful to remove signatures as needed.

Review the solution in the JS SDK: hashgraph/hedera-sdk-js#2491

Alternatives

No response

[0xivanov]

This feature would need to expose an API in all transactions that we have, and all transactions in the future.
Since this functionality is not urgent now, we would like to start the implementation after refactoring the current architecture.