A set of nested portal content definitions.
This class defines an abstract set of common base functionality which forms the foundation of a content container, which is, in reality, realized through creating either a {@link ContentDef.GlobalChannelContainer GlobalChannelContainer} or {@link ContentDef.PageContainer PageContainer} and it's associated contents. All contentwithin the portal is defined and managed within a content container, and belonging to some {@linkplain #getOwnerID() owner}. If you start here, and then proceed to the documentation for those types, you can work your way down the tree of nested definitions, hopefully coming to a more specific understanding of how content is defined within the portal using each of those types. It's also important to note that all type definitions, including this one, are derived from a common {@link ContentDef.Def} base class, so understanding that is alsocritical.
This class is also responsible for managing the runtime {@linkplain #init() initialization} of the content itcontains.