The checks did previously only report the first failure (to not overload the radio link). As we are moving to buffered messages and higher bandwidth links this design choice is not any more in the best interest of the drone operator. We are now reporting all detected failures. To ensure architectural consistency more checks have been moved from the commander mainloop into the respective classes.
* PreFlightCheck: remove unused reportFailures flag
* Commander: pull all pre flight checks together on the PreFlightCheck class
* PreFlightCheck: separate checks into their own files
