feat: change impl to process transaction receipts

[JDawg287]

Description

This PR changes how cross-subnet messages are sent from one subnet to another. Before this PR, we used transaction data and the transactionsRoot as the basis for the cross-subnet messaging protocol. It actually makes more sense to use the transaction receipt data and the receiptsRoot instead, as we can verify the status of the receipt on the target subnet to find out if the transaction was executed successfully on the source subnet, before executing it on the target subnet.

Fixes TP-654, TP-655

Additions and Changes

• Added receiptRoot in the Certificate structure in IToposCore.sol
• Changed the implementation of the sendToken function in the ERC20Messaging.sol contract
• Changed the execute and the corresponding _execute functions in the ToposMessaging.sol and ERC20Messaging.sol contracts
• Adapted the tests

Bug fixes

• Removed an extra variable erc20MessagingContract in the ToposMessaging.test.ts

PR Checklist:

• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added or updated tests that comprehensively prove my change is effective or that my feature works