Add Load in watts and Load Percentage to webgui settings page

Adds Load in watts and Load Percentage to the unRAID webgui setting page
for ups with nompower variable and N/A for those ups without.  Could be
modified so user could input the known nompower for their ups.

https://www.dropbox.com/s/y5gk1boqebf9q03/Screenshot%20from%202014-09-06%2001%3A40%3A45.png?dl=0