Implement: Hierarchy Components

• Implement the Host class in the datatypes package.
• Implement the Manager class in the datatypes package.
• Implement the ManagedObject class in the datatypes package.
• Implement the Topic class in the datatypes package.
• Write unit tests for these classes.

Requires: Implement: StructureComponent and HierarchyComp... (#4 - closed), Implement: Metrics (#6 - closed)