Move the PX4 EKF odom message publication from the bridge main loop to the px4 autopilot class implementation --> to be published at the same frequency the PX4 publishes

Suppression of json and png file of battery thrust calibration to save space on git.

Implementation of the DISARM request.

- addition battery fields
- comment of unused heartbeat message (rx and tx)
- suppression of 2 timer callbacks and move of the functions in the main_loop.
- preparation of a pose topic subscription to send direct pose command to the autopilot

Update of px4 and cf2 class to match modifs

Addition of the use_sim_time launch arg for aos and cf2.

Addition of *use_sim_time* launch arg.

Update of the function spinMotorsForArming for the PX4 to spin motors depending on the autopilot control mode.
Comment of the function spinMotorsForArming in readyToFly (armed state) to prevent conflict with external commands coming from a topic.

Stop state splitted in 2 phases: first decrease thrust to 0, then send disarm command and test if the autopilot is disarmed to transition to idle state.

Use of the autopilot_lib in the drone_bridge_node.

Update of the controller PID  gains

Creation of specific getter/setter functions for autopilotControlMode if parameters must be changed in the autopilot.
Enabling of attitudeThrust control for cf2

Integration of the Crazyflie drone autopilot class

See merge request !1

Use of the override keyword in px4_autopilot.hpp.