Cleanup: Navigator: Vehicle command refactor, FlightTaskAuto: parameter clarification

[MaEtUgR]

Solved Problem

While looking into what would be necessary to command the gimbal back to neutral automatically very close to ground I found that the internal interface for that is not as straight forward as I hoped and instead it's necessary to go through a complicated MAVLink protocol dance in every spot within PX4 that wants to do that.

As part of studying that I came across these pieces which I really at least want to refactor for clarity to enable further improvements.

Solution

• Flight Task Auto crawl speed is not compliant with the parameter naming convention (1. commit)
• More clear MPC_LAND_ALT3 parameter description
• Make navigator function publish_vehicle_cmd consume a reference instead of a pointer and rename it to publish_vehicle_command.
• Follow convention to name messages to publish according to the message name instead of some cryptic abbrevated version.
• Explicitly write float/double literals

Documentation I only adjusted the english version. There seem to be multiple different english versions in other language subdirectories, I still don't understand why such outdated non-translated versions exist.

Changelog Entry

Cleanup: Navigator: Vehicle command refactor, FlightTaskAuto: parameter clarification

Test coverage

It's refactoring except for the reference instead of pointer but if the previous version was ever called with a nullptr it would have hardfaulted.

[github-actions]

No flaws found

[MaEtUgR]

@sfuhrer Thanks for having a look. According to your request I split the individual changes into separate commits. Please let me know if there's anything else I should address 🙏

[sfuhrer]

Thanks for the extreme diligence in updating all the docs as well!