[scd] InterUSS automated test suite should test a USS operating alone through the entire intent lifecycle

[callumdmay]

Is your feature request related to a problem? Please describe.
The InterUSS automated test suite robustly covers interactions and test cases between cooperating USSs, however it currently does not comprehensively test a single USS operating alone - only the create step is tested without other intents in the airspace.

Describe the solution you'd like
We propose extending the InterUSS test suite to exercise the entire intent lifecycle without the participation of any other USS. This provides additional test coverage that a USS can operate independently of other USSs in an area. Each participating USS in an automated test suite run would first demonstrate their ability to create, activate, and delete intents by themselves before testing cooperating scenarios.