[RIG] Added support for rig board

...xM4_stm32f4/stm32f429zi_skyward_rig/core/stage_1_boot.cpp

...2f429zi_skyward_rig/interfaces-impl/arch_registers_impl.h

...4_stm32f4/stm32f429zi_skyward_rig/interfaces-impl/bsp.cpp

...tm32f4/stm32f429zi_skyward_rig/interfaces-impl/bsp_impl.h

...m32f4/stm32f429zi_skyward_rig/interfaces-impl/hwmapping.h

...exM4_stm32f4/stm32f429zi_skyward_rig/stm32_2m+256k_rom.ld

...texM4_stm32f4/stm32f429zi_skyward_rig/stm32_2m+8m_xram.ld

...cortexM4_stm32f4/stm32f429zi_skyward_rig/board_settings.h

miosix/config/boards.cmake

miosix/config/options.cmake