If the API Secret is NOT valid, log its first and last few characters

This should help us confirm whether, for instance, and equals sign has
been dropped from the end of the string.

models/api-key.js

@@ -182,6 +182,8 @@ const isValidApiSecret = (apiKeyRecord, apiSecret = '') => {
   const isValid = password.compare(apiSecret, apiKeyRecord.hashedApiSecret);
   if (isValid !== true) {
     console.log('The given API Secret is NOT valid for the given API Key record.');
+    const redactedApiSecret = apiSecret.substring(0, 3) + '...[snip]...' + apiSecret.substring(apiSecret.length - 3);
+    console.log(redactedApiSecret);
     return false;
   }