Remove unused app/constants/ dir

All the constants are defined here:
https://github.com/openbmc/phosphor-webui/blob/master/app/common/services/constants.js
Constants are injected as part of app.common.services.
This environment-constants.js or environment-constants.json could
be repurposed to configure features but going with something else,
https://gerrit.openbmc-project.xyz/#/c/11311/.

Tested: Quick manual regression test on the pages.
Change-Id: I59ba4f47fe8a927cb5f68a2657dfea9c61cd5f28
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/app/users/index.js b/app/users/index.js
index 695c294..1972c4c 100644
--- a/app/users/index.js
+++ b/app/users/index.js
@@ -9,7 +9,7 @@
   'use strict';
 
   angular
-      .module('app.users', ['ngRoute', 'app.constants', 'app.common.services'])
+      .module('app.users', ['ngRoute', 'app.common.services'])
       // Route configuration
       .config([
         '$routeProvider',