Test rollups according to design doc

This test sets up and verifies the device and site rollups according to this design document:
https://confluence.oceanobservatories.org/display/syseng/CIAD+SA+OV+Observatory+Status+and+Events

Currently, only the instrument devices and sites are being tested because the platform device/site statuses are not rolling up properly according to the diagram.  (The diagram's entities have been numbered, and correspond to the numbering in the test).

`test_complex_rollup_structure_partially` should be removed when `test_complex_rollup_structure` works properly.