nucleo-144 combines 3 different ST boards. This approach is inconsistent with
the support for the rest of the nucleo boards, where each board is in separate folders.
Also nucleo-144 is no longer reserved for STM32F7 chips but other families also use this format.
After this commit nucleo-144 is divided into 3 boards:
- nucleo-f746zg
- nucleo-f767zi
- nucleo-f722ze
raiden00pl