Add workaround to build on VS/Pio (Windows)

[Xelack]

Only to enable build on VS/Pio (Windows) because the "date( +%%Y.." not work on this context.

My solution consist in move a part of CPPDEFINE of the platformio.ini file into prebuild python script. That work for all build context because python is cross platform but I cannot confirm by testing because I don't have others kind of systems. (Don't hesitate to tell me if it's ok or not in these others systems)

I hope that will be helpfull...

[SamJCKnox]

Have tested this pull and works in both windows and linux versions of VSCode