Add titano update pyportal pins

[tyeth]

This is a rebased version of #109 with a couple of tweaks to both PyPortals, mainly:

• Boot LED was set to PWM, causing reboot.
• Analog pins backing names were named incorrectly giving no Light sensor data (A2 gets translated to Pin 2, not A2, so we need pin 14 for A0 etc, see https://github.com/adafruit/ArduinoCore-samd/blob/master/variants/pyportal_m4_titano/variant.cpp#L65