VS CODE IDE & OpenOCD debugging support

[kamejoko80]

Hi @danngreen,

You know, vs code is a practical and lightweight IDE so I'd like to introduce how to add vs code IDE and how to configure the OpenOCD gdb server.

For a demonstration, I created a repo, you can run vs code and open the folder "mp1-boot".

This is just a sample for mp1-boot, you can organize the IDE for other programs if needed.