Stop using Bluebird.delay and Bluebird promise::delay

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/utils.js

@@ -708,3 +708,8 @@ module.exports.ensureNoTrailingSlash = function(url) {
         return url;
     }
 };
+
+// Returns a promise which resolves with a given value after the given number of ms
+module.exports.sleep = (ms, value) => new Promise((resolve => {
+    setTimeout(resolve, ms, value);
+}));