feat: add tx hash retrieval in wallet plugin

lib/plugins/wallet/zcashd/zcashd.js

@@ -151,11 +151,18 @@ function checkBlockchainStatus (cryptoCode) {
     .then(res => !!res['initial_block_download_complete'] ? 'ready' : 'syncing')
 }
 
+function getTxHashesByAddress (cryptoCode, address) {
+  checkCryptoCode(cryptoCode)
+    .then(() => fetch('getaddresstxids', [address]))
+    .then(_.mapKeys(() => 'txid'))
+}
+
 module.exports = {
   balance,
   sendCoins,
   newAddress,
   getStatus,
   newFunding,
-  checkBlockchainStatus
+  checkBlockchainStatus,
+  getTxHashesByAddress
 }