- include icm20948 on most boards by default
- create more test variants for default boards near flash limit (cuav_nora_test, cuav_x7pro_test, holybro_durandal-v1_test)
- currently the main change is that it reduces the max number of ORB multi instances to 4, but usage will be expanded as needed
- limits number of EKF2 multi instances to 2.
- enabled on all cortex m4 boards
- always check with state machine before reboot/shutdown
- respect BOARD_HAS_POWER_CONTROL (shutdown from command, low battery, power button)
- px4_shutdown_request add optional delay and always execute from HPWORK
- px4_shutdown_request split out px4_reboot_request