MXS-3013: Add reload service MaxCtrl command

The command currently reloads the users of a service but it can be used to
reload other parts of it as well (e.g. encryption keys).

maxctrl/test/reload.js

@@ -0,0 +1,12 @@
+require('../test_utils.js')()
+
+describe("Reload Commands", function() {
+    before(startMaxScale)
+
+    it('reload service', function() {
+        return doCommand('reload service RW-Split-Router')
+            .should.be.fulfilled
+    });
+
+    after(stopMaxScale)
+});