split MobileTemplateWML into its own class

The autoloader expects this as it is specified in
the classes array which looks for classes in
individual files.

You can see this if running the autoloader tests in
core. So this is probably what should be done.

Change-Id: Ia5ef4b267542bfa7491f0141b6ed6a46f7a00fef
Merge "split MobileTemplateWML into its own class"