Flow: Observing outgoing cross-chain transactions to EVM-compatible chains

Observation and processing of incoming cross-chain transactions starts in the observeOutTx() function. This function currently runs every three seconds. It simply queries for the outgoing transaction tracker for a specific chain from the x/crosschain module. Afterwards, it loops through each transaction hash in the tracker, queries for the receipt and actual transaction using the hash, and then stores the receipt and transaction data into the outTXConfirmedReceipts and outTXConfirmedTransaction maps respectively, indexed by the nonce.