Move to CODAL build system

[microbit-carlos]

As Yotta is deprecated and hasn't been updated in a long time, installing it is getting more and more difficult.

As Yotta uses CMake under the hood, and CODAL's build.py does as well, we should look into moving away from Yotta to a simpler build system we can easily maintain.

A few thoughts about this process:

• Yotta has a hierarchy system, so that targets can inherit configuration and properties from parents.
  • We don't need to replicate this system, just figure out what the final configuration for the micro:bit target might be, and ensure we are applying the same configuration
• Yotta autogeterates some CMake files
  • Similarly here, we don't need to replicate this system, but figure out the final CMake configuration and use that
• Ideally we'd want build.py to create an identical build that Yotta (assuming same version of all other tools used)
  • As it is unlikely the two builds will by byte-to-byte identical we need to identify the exact memory fooprint of the Yotta builds and ensure the build.py builds are the same
• We need to decide if we want to reuse the current repos or create new ones
  • It's likely we will need to include additional files somewhere, and they might clash with the original Yotta build system, so we need to figure out if we want to try to use the same repos for build.py and Yotta, or duplicate the content and keep them separated
  • https://github.com/lancaster-university/target-mbed-gcc
  • https://github.com/lancaster-university/yotta-target-bbc-microbit-classic-gcc
  • https://github.com/lancaster-university/yotta-target-bbc-microbit-classic-gcc-nosd
  • https://github.com/lancaster-university/microbit
  • https://github.com/lancaster-university/microbit-dal
  • https://github.com/lancaster-university/mbed-classic
  • https://github.com/lancaster-university/BLE_API
    • https://github.com/ARMmbed/ble-nrf51822
  • https://github.com/lancaster-university/nrf51822
    • https://github.com/ARMmbed/ble
  • https://github.com/lancaster-university/nrf51-sdk