AP_RangeFinder: initial support for the DFRobot07 lidar

[landswellsong]

Support for DFRobot07 which is also sold as VSemi Atom

Documentation: https://dfimg.dfrobot.com/nobody/wiki/1840a7b7b14e02f3566e0cef5b51e9ba.pdf

Implementation caveats:

• UART only for now;
• 50 ms fixed data rate, can be synced up with update() but it involves waiting for the result since the sensor does take a bit of time to process commands;
• there are a bunch of values coming from the sensor that don't have a clear mapping to anything in AP so they are ignored for now, although potentially can be used to estimate the signal quality;

Code quality and style questions that I'd love to have a senior developer feedback:

• Should the initialization be done like I did in update() or should I rather have overriden init_serial? Given how sensor works it would mean the thread that runs it needs to be waiting for a while.
• Is the offset macros fine or should I rather make structures/unions for a more clear picture of the data layout?
• The CRC32 in the sensor seems to work in opposite bit order reflection mode in comparison to the AP implementation (and frankly any standard implementation). Is it okay to put extra CRC32 utils hidden like I did or should I move that to AP_Math / optimize it etc?

[landswellsong]

SITL test in the room conditions:

[landswellsong]

https://github.com/ArduPilot/ardupilot/actions/runs/11257361975/job/31301422237?pr=28366#step:9:1282

Right, guess I'll rewrite the offset part to work with ARM and test that locally too.

[peterbarker]

Sorry, very brief review only.

[landswellsong]

Resolved all the issues, removed any sleeping whatsoever. Will test on the weekend on the sensor.