Support Hierarchical Projects

[jobrs]

When the target project/domain has child-projects, the API calls cascade to the child-projects, so that the audit-viewer of the main project does not have to traverse all the child-projects.

When called against the main project, the API act like the child-projects had been merged with the main project. That means that the /events call returns all the events of child-projects. Likewise the /attributes API returns existing unique values in not only the main but also the child projects.