Generate doc root doxygenlayout file, as well as devices stuff, based on main
Makefile $(TARGETS) and template files. Avoids painfull sync/merge of 20 files+
when adding a new device.
bonus : allow to build only one device doc easily (make TARGETS=stm32f0 doc)
regression: we currently loose device "fancy" naming as device name is
guessed (toUpper()..) from folder name.
Guillaume Revaillot