Add NetworkInterfaces controller and tests

The controller only responds to GET calls, returning either
one of all of the configured interfaces. Forkers may extend
this to allow their users to add interfaces at run time (why?)
Add alias for parameter parsing method.
Add 'update' functionality to NetworkInterfaceController

So that the user can update the "mode" on the interface (eg
change from dhcp -> static, or change which dhcp profile it
uses).