Bluetooth: tests: Add tests for Bluetooth privacy

Add tests to check the following aspects of the Bluetooth privacy feature:

- On device privacy mode, scanner shall accept advertising packets from
  peer with any address type. That, even if they have previously exchanged
  IRK;
- After devices have exchanged IRK, they must correctly resolve RPA.

Signed-off-by: Théo Battrel <theo.battrel@nordicsemi.no>