Extract boards data from platformio

[macbre]

https://docs.platformio.org/en/latest/core/userguide/cmd_boards.html

$ platformio boards attiny88

Platform: atmelavr
============================================================================================================================================================================================================================
ID        MCU       Frequency    Flash    RAM    Name
--------  --------  -----------  -------  -----  ----------------
attiny88  ATTINY88  8MHz         8KB      512B   Generic ATtiny88