embedding Arancino platform into platformio

[artynet]

As described in the object, this PR adds the Arancino.cc platform which is a comprehensive IoT set of boards and upload tools.

In the very specific, two boards have been added :

• Arancino (samd21 based)
• Arancino Mignon (samd21 based)

and two platform-specific upload tools :

• arancino-ota
• arancino-ota-no-gui

with their respective upload protocols :

• tool-arancino-ota
• tool-arancino-ota-no-gui