Replaces the deprecated ESP32 calibration API with the "line" method
instead.
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
This is a code factoring to have the Python bindings in one location, and
all the ports use those same bindings. At this stage only esp32 implements
this class, so the code for the bindings comes from that port.
The documentation is also updated to reflect the esp32's behaviour of
ADCBlock.connect().
Signed-off-by: Damien George <damien@micropython.org>
