Add Source and Makefiles for Hello_World example program #28
Description
The Hello_World program is a great way to run various executables (other than MicroPython) on the synthesized chip/chiselwatt, but without source and instructions for what objcopy commands to use, it doesn't serve as an example for how to use this introductory stub as a template for anything else.
It would be nice to have a source and compilable version of the Hello_World so that generic programs can be made to test/use chiselwatt.