CAN: add library and overlay configuration

[dani-clo]

Add CAN/CANFD Arduino library with board overlay updates

The library provides a simple Arduino-style API built on top of Zephyr CAN drivers.

Depends on Zephyr PR:

• zephyr#15 (CAN configuration support for Uno Q, Portenta H7, Portenta C33)

Changes

1. New Arduino library:

   • CAN (with CAN and CANFD support)

2. Device tree overlay (.overlay) updates for:

   • arduino_uno_q
   • arduino_giga_r1
   • arduino_portenta_c33
   • arduino_portenta_h7

3. Added 3 ready-to-run examples

Testing

Tested on all listed boards for both CAN and CANFD functionality.

[CLAassistant]

All committers have signed the CLA.

[github-actions]

Built 0.53.2-0.dev+92e66ef0

CI run FAILED: 🔥 portentac33

Artifact	Board	Core	Tests	RAM	Sketches	Warnings	Errors
✅ zephyr_contrib	ek_ra8d1	📗	✅	11.9%	2	-	-
	frdm_mcxn947	3 🏷️	✅	58.0%	2	-	-
	frdm_rw612	1 🏷️	✅	83.0%	2	-	-
🔥 zephyr_main	giga	4 🏷️	✅*	54.6%	50	8	-
	nano33ble	1 🏷️	✅*	78.7%	22	8	-
	nano_matter	📗	✔️*	⚠️ 85.7%	20	8	(2*)
	niclasense	2 🏷️	✅*	⚠️ 87.3%	20	8	-
	opta	4 🏷️	✔️*	46.7%	54	8	(2*)
	portentac33	🔥	Core build failed!
	portentah7	3 🏷️	✔️*	47.4%	64	8	(2*)
✅* zephyr_unoq	unoq	📗	✅*	26.4%	68	8	-

Legend

Board	Test	Status description
🔥	🔥	Test run failed to complete.
❌	🔴	Test completed with unexpected errors.
✔️*	🚫	Test completed with errors, but all are known/expected.
✅*	🟡	Test completed with some warnings; no errors detected.
✅	🟢	Test passed successfully, with no warnings or errors.
🌑	🌑	Test was skipped.

Caution

zephyr_main is blocked due to failures on portentac33!