Logging start / restart by Mavlink command

[ARACE-DEV]

Feature request

Is your feature request related to a problem? Please describe.

1. Disarmed logging can only started by setting up LOG_DISARMED to 1. But if set to 1, it logs always until LOG_DISARMED is set to 0 again.
2. Endurance tests often creates huge logs in which it is difficult to find and review a specific period or event

Describe the solution you'd like
Add a possibility of starting / restarting logging by Mavlink command, through MissionPlanner, or other QGC apps.

Operation :

1. If the vehicle is disarmed, this command triggers a log recording start.
2. If logging is already running, this command ends up the actual log and starts another one. This can be useful to separate specific sections of a test flight into different logs.
   Especially when raw IMU logging is enabled, which increases log sizes by a lot.

Describe alternatives you've considered
I didn't find another way of restart logging in the air.

Platform
[X] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

Additional context
Possible MissionPlanner command in the Action menu: