New variant BLUE_F407VE_Mini

[edogaldo]

Hello, I'd like to push subject variant for this board, ref. #329.
It's a minor rework based on variant BLACK_F407VE, ref. #327.

[edogaldo]

What's wrong with the checks?!

  --> BLUE_F407VE_MINI FAILED
In file included from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/system/Drivers/CMSIS/Device/ST/STM32F4xx/Include/stm32f4xx.h:250:0,
                 from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/cores/arduino/stm32/stm32_def.h:16,
                 from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/cores/arduino/stm32/clock.h:43,
                 from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/cores/arduino/wiring_time.h:23,
                 from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/cores/arduino/wiring.h:38,
                 from /home/travis/.arduino15/packages/STM32/hardware/stm32/*/cores/arduino/Arduino.h:32,
                 from /tmp/BuildOutput_2018-09-21_15-11-16/BLUE_F407VE_MINI/sketch/BareMinimum.ino.cpp:1:
/home/travis/.arduino15/packages/STM32/hardware/stm32/*/system/Drivers/STM32F4xx_HAL_Driver/Inc/stm32f4xx_hal.h:46:32: fatal error: stm32f4xx_hal_conf.h: No such file or directory
 #include "stm32f4xx_hal_conf.h"
                                ^
compilation terminated.
exit status 1

[edogaldo]

Decided to bind default SPI to SPI2 over PB12-15:

[fpistm]

Ok for me, very closed to BLACK_F407VE
Note that I could not test the board as I do not have it.

[fpistm]

@edogaldo
Let me know when you think it's ready to merge.

[edogaldo]

@fpistm: I could successfully test bink and i2c scanner (with print on UART1).
To me it's safe enough for merging.

Thanks in advance and best, E.