Add support for "Adafruit Metro M4 Express AirLift (WiFi) - Lite"

[alborzs]

Feature Request:

This is a request to support Adafruit Metro M4 Express AirLift (WiFi) - Lite. Adafruit just released a new board with Cortex M4 and an ESP32.

Read more about the board at https://www.adafruit.com/product/4000 But here is some data to get you intrested:

• Cortex M4 core running at 120 MHz
• Floating point support with Cortex M4 DSP instructions
• 512 KB flash, 192 KB RAM
• 32-bit, 3.3V logic and power
• Dual 1 MSPS DAC (A0 and A1)
• Dual 1 MSPS ADC (8 analog pins)
• 6 x hardware SERCOM (I2C, SPI or UART)
• 22 x PWM outputs
• Stereo I2S input/output with MCK pin
• 10-bit Parallel capture controller (for camera/video in)
• Built in crypto engines with AES (256 bit), true RNG, Pubkey controller
• 64 QFN

[ivankravets]

Please re-test with upstream version http://docs.platformio.org/en/latest/platforms/atmelsam.html#upstream