AP_EFI/AP_PiccoloCAN: Add Currawong ECU support

[reilly-callaway]

• Reads telemetry data over CAN and pass to existing AP_EFI_Backend.
• Configurable to send throttle commands over CAN to a single ECU.

Example with Currawong ECU connected to CubeOrange over CAN. Shows EFI mavlink status in Mission Planner (matching data in Currawong's internal tool) with throttle set by Ardupilot:

[hendjoshsr71]

Quick comment to get past your first CI error:

Add the following under here should fix it

ardupilot/Tools/autotest/param_metadata/param.py

Line 115 in 910406e

'kg/m/m' : 'kilograms per square meter', # metre is the SI unit name, meter is the american spelling of it

         'kg/m/m/m'  : 'kilograms per cubic meter',

We will eventually need to clean up you commit list a bit by squashing the "clean up" commits. ArduPilot doesn't use merge commits. Instead we rebase our working branch on top of the master (development) branch. https://ardupilot.org/dev/docs/git-interactive-rebase.html

I can help you with GIT if needed?

[hendjoshsr71]

Some small changes.

Note: I didn't look over the PiccoloCAN parts yet

[reilly-callaway]

Rebased on top of master and to clean up commit history, happy to squash it down more if you'd like.

[hendjoshsr71]

The commits look reasonable enough to me.

Some style things. I didn't go through the generated code.

I'm probably not the person for reviewing the CAN changes. As I'm not as familiar with the their structure enough to ensure thread safety.

This one is outside of my scope to approve. But I'm glad to see it built locally now :)

[SchrodingersGat]

@hendjoshsr71 any further requirements for review on this?

[tridge]

looks nice!

[reilly-callaway]

@tridge @peterbarker Any updates on having this approved?

[tridge]

@reilly-callaway needs a rebase as conflicted, then ping me to merge this

[reilly-callaway]

@tridge Rebased and all tests passing. Should be good to merge.

[peterbarker]

Merged, thanks!