README.md: Add OSS overview
README.md: Add OSS overview

Add a brief OSS overview.

Signed-off-by: Leon Anavi <be92910ae7bb6f58bb9b7c6f845bc30640119592@anavi.org>

leon-anavi/rpi-examples,leon-anavi/rpi-examples,leon-anavi/rpi-examples,leon-anavi/rpi-examples