examples: add ina260

[jeanthom]

Summary

Add example application for INA260 current/voltage/power sensor driver. Driver PR is currently being reviewed here: apache/nuttx#18430

The program periodically outputs the voltage, current and power measurements from the chip.

Impact

Add ina260 program.

Testing

Tested on top of NuttX 12.12.0, compiled on macOS for STM32F407-DISC1. Output looks like this:

nsh> ina260
U= 23898mV I=   571mA P= 13680mW
U= 23870mV I=   728mA P= 17400mW
U= 23862mV I=   782mA P= 18680mW
U= 23858mV I=   796mA P= 19030mW
U= 23857mV I=   805mA P= 19200mW
U= 23857mV I=   805mA P= 19200mW

[linguini1]

Hi @jeanthom , just putting a change request here to avoid accidentally merging before the corresponding driver is merged first :)