This way third parties can use PX4FirmwarePlugin as base class and
override as needed

Convert bool settings to SettingsFact

Use component id from heartbeat

Also added new FirmwarePlugin::brandImage support

_finalize methods need information which is not available if all you
have is a mavlink_message_t

before, with a version of eg. 1.5.0, the user was wrongly notified.

Also change Plan Element selection ui