Existing users of orb_exists:
- logger (dynamic subscribe to multi-instances)
- mavlink (orb subscription)
- sdlog2
- preflightcheck (check for home_position)
- wait_for_topic shell command (it's not used)
- orb_group_count() (sensors: dynamic sensor addition)

All use-cases benefit from the changed semantics: they are really only
interested if there is a publisher, not another subscriber.

mc_att_control: defualt parameters set maximal acro rates to 2/1.5 turns per second for roll,pitch/yaw

mc_att_control: use expo input for acro mode to allow for high input rates without loosing input sensitivity

we're out of flash again :/

The board id was used as flight id which does not make sense.

arming_state_changed was not set in all places where an arming transition
occurred, for example when calling arm_disarm() from auto-disarm.

We did not notice because the state is published with at least 5 Hz already.

The size in g_per_item_size[item] is the real struct size
+ DM_SECTOR_HDR_SIZE bytes of header and the backend functions were
not taking in care it. So a call to dm_write() with more bytes than
the real struct is allowed, causing corruption in the header of the
next item.

Kudos to jeonghwan-lee for finding it. https://github.com/PX4/Firmware/issues/7927

Adding Sugnan Prabhu as maintainer for Intel Aero.
With great power comes great responsibility!

This is more flexible, allowing a combination of sets.

The default enables the same set & rates as before

DroneCore uses the attitude quaternion, and not the attitude
Euler angles.

The gimbal attitude is required by DroneCore.

aerofc-v1 uses a STM32F429V not STM32F427V.

There was and extra "nuttx" dir:
	cp: cannot stat '/home/lucas/p/dronecode/PX4/Firmware/build/aerofc-v1_default/NuttX/nuttx/nuttx/.config': No such file or directory
	FAILED: NuttX/CMakeFiles/menuconfig

And the board fixup being executed from the wrong working directory:
	nuttx-configs/aerofc-v1/nsh/defconfig
	fatal: Path 'nuttx-configs/aerofc-v1/nsh/defconfig' does not exist in 'HEAD'

- initialize rc lost with true
- refactor for simpler downstream code-plugin
- allow for the addition of different binding commands
- fix st24 RC lost logic