Set ResourceManager tracking URL to resources path.

The resource manager tracking url is currently set to the host and port only. There is nothing exposing the fact that you can append 'resources' to the path to get a list of containers and information about each container.

This was done because the YARN api was to working properly at the time, but we should re-investigate to see if this is still the case, or perhaps serve some base page there that links to the resources page, plus anything else we decide to add in the future.