ESP-01 header renamed to AUX, and expanded to 12 pins from 8
pins. Pins 1-8 still accommodate the ESP-01, with expansion to full
SERCOM 4-pad support to allow for SPI and I2C on that expansion port
with additional GPIO control.
Update pins.c with additional signals provided AUX_1-8, along with
UART, SPI, I2C name usage as aliases to appropriate AUX_1-8
signals. Additionally, add several alternate names specific to several
expansion modules - the ESP-01, and the ATW-01 using the WINC_1500
(SPI) w/interrupt and control needed for the WINC - with assignments
to module pin positions.
Re-work SERCOM assignments to accommodate the above from other parts
of the board, which required moving a SERCOM or two around in order to
accommodate the 4-pad sercom pin mapping on the AUX port.
Built and tested using latest from 'main':
Adafruit CircuitPython 6.2.0-rc.0-70-ga1562430f-dirty on 2021-04-05;
BDMICRO VINA-D51 with samd51n20
f66fc25d95