Add ina260 example

[peterharperuk]

This can be used to monitor power usage of a Pico device.

[peterharperuk]

@Louis31423142 As discussed, could you test this and make sure it works? I'll add some wiring diagrams and a readme before submitting. Thanks.

[Louis31423142]

@Louis31423142 As discussed, could you test this and make sure it works? I'll add some wiring diagrams and a readme before submitting. Thanks.

Example works for me