Usability enhancements: allow login on enter key, added icons on login and logout buttons, added placeholder on gas modal

wwwroot/js/login.js

@@ -9,4 +9,9 @@
             errorToast("Invalid Login Credentials, please try again.");
         }
     })
+}
+function handlePasswordKeyPress(event) {
+    if (event.keyCode == 13) {
+        performLogin();
+    }
 }