Tempest cleanup: improve iterating over projects

Currently cleanup iterates over projects and deletes all resources
tied to a particular project. However, most of the resources can be
deleted all at once without iteration over the projects.
This will fix the mentioned bug and also make the tool much more
efficient as we'll avoid many iterations and queries.

Closes-bug: #1830943
Change-Id: I82c7899a32bee0e714e71d703195085e10ea224f
2 files changed