überSpark: add tool-chain support for platform definitions

This task adds tool-chain support for platform definitions. A platform is essentially a build and verify target. The currently supported platforms are:

  1. uberspark/platforms/pcintel-generic/x86/32-bit/core-gen1
  2. uberspark/platforms/pcintel-generic/x86/32-bit/core-gen4
  3. uberspark/platforms/rpi3/armv8/32-bit/cortex-a53



Added PR and merge info to OP. Tested build successfully with uberXMHF and uobjcoll ARM TFA. Closing topic thread.