drivers: sensor: ams_as5600: Rewrite driver to enhance configuration

This is a complete rewrite of the existing AS5600 driver. Device registers
and configuration are supported through the fetch and get API using
channels and attributes. The device tree binding was updated to cover all
configurable options of the device. The device is now initialized to the
state defined in the device tree on init or its power on reset state if a
setting is not configured.

Signed-off-by: Cameron Ewing <cameronramsayewing@gmail.com>