Respect package name for named scalar types also

[stmeissner]

The RAML Doc generator organizes the flattened RAML type files into subfolders according to the package names declared for the types, but currently only for type: object. We would like to have the same behavior for named scalar types also, like for type: string.

Example

The generated flattened version of this file:

#%RAML 1.0 DataType
(package): Common
displayName: Locale
type: string

should be found in subfolder Common instead of the root folder.