Improvement - NHibernate configuration - Add attributes to mark classes for NHibernate mapping

[xhafan]

Currently one needs to override methods in NhibernateConfigurator to customize NHibernate mapping.

Examples:

• to map a class as NHibernate component, one needs to override BaseNhibernateConfigurator.GetComponentTypes() (code sample here)
• to map a class hierarchy as a discriminated type saving the whole class hierarchy into one table, one needs to override BaseNhibernateConfigurator.GetDiscriminatedTypes() (code sample here)

The same goes for other methods in BaseNhibernateConfigurator (GetIncludeBaseTypes, GetIgnoreBaseTypes).

It would be handy to have a set of attributes to mark a class as NHibernate component, or mark it as a discriminated type, or mark a base class as "included" in mapping or "ignored" from mapping.