Refactor transaction sync module

Refactors the transaction sync module for better organization.

src/utils/sync/transaction/index.ts

@@ -0,0 +1,10 @@
+
+import { uploadTransactions } from './uploadTransaction';
+import { downloadTransactions } from './downloadTransaction';
+import { deleteTransactionFromServer } from './deleteTransaction';
+
+export {
+  uploadTransactions,
+  downloadTransactions,
+  deleteTransactionFromServer
+};