[Data-modeling] Draft motorcycle domain

[Ed Laurent]

I created a draft Motorcycle Domain for review. It is similar to the
Automotive Domain but doesn't really seem to fit within that Domain.
'Motorcycle model year' is a good place to start with the type viewer.
The '2008 Harley-Davidson Sportster 1200 Roadster' topic is filled in
pretty well if you want to see how that looks. I already see that I
should set MSRP to a CVT with Price and Option properties. Let me know
what you think.

-Ed