Finish Raspberry pi baremetal port

[alloncm]

There are still uncompleted tasks:

• Merge the rpi_gpio module to the baremetal project to create a RPI project with feature to run baremetal (the peripherlas are really look alike in the code base)
• Add support for roms-folder from the image sd card
• Support proper shutdown from software side
• Add support for saves
• Support other rpi's and cpu's, currently the code is only tested on cortex-a72 (and some code assumes it compiled only for this cpu) so add support for other cpu's and arrange the code for that
  • replace the target-feature=+virtualization with target-cpu=cpu for the compiled cpu
  • Add .ifdef where necessary to add support for coretx-a53 and more
  • Add a rendering core that will handle the rendering to boost performance - Not sure if necessary (on RPI4 its not but might be on zero2)
• More testing on hardware (hopefully get another rpi zero2)

[alloncm]

I can use the armv7a-none-eabi target instead using those target feature flag -Ctarget-feature=-soft-float which seems to disable the soft-float feature, I believe it wise to also turn on neon and vfp3/4 but perhaps they should be turned on automatically if ill specify the target cpu