Revise payment tutorials, add/remove screenshots

_code-samples/modular-tutorials/send-xrp.js

@@ -0,0 +1,28 @@
+// *******************************************************
+// ******************** Send XRP *************************
+// *******************************************************
+async function sendXRP() {   
+  const net = getNet() 
+  const client = new xrpl.Client(net)
+  await client.connect()
+  let results = "\nConnected. Sending XRP.\n"
+  resultField.value = results
+  const wallet = xrpl.Wallet.fromSeed(accountSeedField.value)
+  const sendAmount = amountField.value  
+// -------------------------------------------------------- Prepare transaction
+  const prepared_tx = await client.autofill({
+    "TransactionType": "Payment",
+    "Account": wallet.address,
+    "Amount": xrpl.xrpToDrops(sendAmount),
+    "Destination": destinationField.value
+  })
+// ------------------------------------------------- Sign prepared instructions
+  const signed = wallet.sign(prepared_tx)
+// -------------------------------------------------------- Submit signed blob
+  const tx = await client.submitAndWait(signed.tx_blob)
+  results = "\nBalance changes: " + 
+    JSON.stringify(xrpl.getBalanceChanges(tx.result.meta), null, 2)
+  resultField.value = results
+  xrpBalanceField.value =  (await client.getXrpBalance(wallet.address))
+  client.disconnect()    
+} // End of sendXRP()