Add system diagnostics page to the config section

Fixes [MLHR-1453](https://malhar.atlassian.net/browse/MLHR-1453).

![image](https://cloud.githubusercontent.com/assets/1390651/4567661/59c870c8-4f33-11e4-9793-ac1f12568607.png)


Squashed commit of the following:

commit 061416e965fbe4f1be90ac7693f12b763ce98902
Author: Andy Perlitch <andy@datatorrent.com>
Date:   Wed Oct 8 14:35:45 2014 -0700

    MLHR-1453 #resolve

commit e336be1ae55ec5a774d640f6e9481063cb0e4617
Author: Andy Perlitch <andy@datatorrent.com>
Date:   Wed Oct 8 14:05:18 2014 -0700

    add gateway info model

commit 1ccc3d218946f673c5cd5810687b36ab55c67535
Author: Andy Perlitch <andy@datatorrent.com>
Date:   Wed Oct 8 13:58:14 2014 -0700

    remove unnecessary entry of GatewayRestart in urls

commit 48494e1e82e17ae4040f8622bd368213b6190cc8
Author: Andy Perlitch <andy@datatorrent.com>
Date:   Wed Oct 8 10:59:01 2014 -0700

    added systemDiagnostics page module

commit 61aac05a52f4661b5774ae076cc508c0536ac092
Author: Andy Perlitch <andy@datatorrent.com>
Date:   Wed Oct 8 10:57:49 2014 -0700

    removed unnecessary install script