Allow advanced search to display other component objects

1. Display a selector below the "profile" selector on advanced search to allow the user to choose what object to display search results

2. if user selects an object, we switch to that mode, i.e. as if we are doing a component search and we display component results and component tasks

3. We will not persist this as a smart group, since there is code that expects smart group to return contacts, not components

4. The initial implementation will support: Contributions, Participants and Activities