Delete obsolete files

[DanielJDufour]

There's some files like about.yml and hound.yml. If we're not using them anymore, we should delete them.

[froi]

@DanielJDufour the about.yml is used by GSA during they code.json creation. In any case, I think it should be renamed to .about.yml. I'll try to confirm that.

[DanielJDufour]

We should also create a file that includes a table in Markdown that lists many of these files and what their purpose is.