Drivers: set CM8JL65 signal_quality invalid beyond bounds

[nicovanduijn]

This changes the driver for the CM8JL65 lidar slightly, now populating the signal_quality flag.

It is set to -1 for unknown signal quality if the measurement is within the bounds (with some margin) defined in the datasheet.

It is set to 0 (denoting invalid signal) if the measurement lies outside that range.

This helps a lot with no-GPS take-offs, since the ground estimate initializes properly with the changes from #12950

[dagar]

We should capture this generically as the default behavior for all distance sensors that don't provide a real quality (most of them?).

The current idea is to push everything we expect PX4 side into PX4Rangefinder (https://github.com/PX4/Firmware/blob/master/src/lib/drivers/rangefinder/PX4Rangefinder.hpp), then try to keep the drivers as simple as possible (raw data acquisition). Example: #12947