WIP: Add SPDX-License-Identifier to scripts #1

WIP, DO NOT MERGE

This is my attempt at adding SPDX-LIcense-Identifier to files that would benefit from it. A broader license note is still needed which will be another commit.

Current issues with this PR:

• I forgot to add a copyright note to the board/myna-player-odyssey/ files
• Copyright is probably wrong for the packages/ since they're probably copied from somewhere else and/or modified. We need to credit the original authors and note that the files are modified

First issue fixed, just need to verify credits and copyright for packages

I'm merging this in to #2 since they're related