Added the ability to specify explicit db type's for a property type using an overloaded ctor argument. This allows us to specify explicit db types for properties without having them get overwritten during the repository saving logic which will always reset it to be the db type of the underlying property editor. In the case of our built-in membership properties we do not want this to happen. Fixes some unit tests. Removes built-in props from being included in the property types on the profile model on the front-end.