boards/shields: arduino: add few zephyr_i2c labels

Some of these are allegedly ESLOV connectors and have an extra
identification pin, but there's adapters on the market to use them with
qwiic modules, let's label them so they can be used with other
zephyr_i2c shields.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>