pandad tests

[adeebshihadeh]

Now that we support multi-panda setups and two different MCU types, we should have a comprehensive test suite to cover pandad. This test should be run on both the master-ci and release builds.

some test cases to start with

• [ ] flashing with out of date fw
• [ ] flashing while in DFU
• [ ] flashing while in bootstub
• [ ] flashing bootstub when going from release to devel
• [ ] skip flashing when version matches
• [ ] internal panda: recover with GPIO
• [ ] internal panda: reset via GPIO if panda doesn't show up over USB
• [ ] muilti-panda ordering