Board script

[CezaryGapinski]

New feature with script for generating board sources, kconfig and "make" files based on board description from json file.

[FreddieChopin]

Can I manually squash all these commits to just two? One which adds the script with required files, second which regenerates the files.

[CezaryGapinski]

If it sufficient to you, I have nothing against it :).

[FreddieChopin]

I've merged your branch with minor changes:

• some .jinja files did not have a new-line at the end - I've added one,
• some .json files had extra empty line at the end - I've removed that,
• the python script had some empty lines with tabs - I removed the tabs,
• two .json files did not have the buttons block indented - I've fixed that,
• minor editing changes to the Makefile commit (line lengths, names, order, etc.),
• I've added the entry to CHANGELOG.md.

Thanks for your effort!