bugfix/dont modify current transactions

[estebanmino]

When fetching transactions from API, if a fetch and a transaction are made in in the same block we have register of, the API transaction will overwrite the one from the app.

Example

1. I'm sending a swap transaction with id (random()) 1 and transaction hash 0x1 coming from TransactionController.addTransaction
2. Mobile app saves the swap information needed to display to users
3. When transaction is confirmed, fetching the API will get the same tx with transaction hash 0x1, as normalizeTx is generating a new id 2 (random() again)
4. We ignore local transactions in favor of the remote transactions (here)
5. Transaction with id 2 and hash 0x1 will be saved.

For swaps and also if we want to know which transactions are coming from the app, is the wrong behavior because we'd like to save the original transaction with id 1, because we have other information depending on that original transaction.

So with this PR the idea would be to save local transactions first and then remote transactions, not the inverse.

[Gudahtt]

LGTM!