Add support for Hybrid Oval Cherry MX/Alps/Matias footprints.

Created by: egladman

Add support for Hybrid Oval Cherry MX/Alps/Matias footprints.

I'm the maintainer of keebs.pretty. I'll like to merge my footprints into the official KiCAD library.

Please see egladman/keebs.pretty#7 for additional context and justification.

Datasheets/Specs:

• https://cdn.sparkfun.com/datasheets/Components/Switches/MX%20Series.pdf
• http://matias.ca/switches/quiet/

The keebs.pretty repo is licensed under CERN Open Hardware Licence. I'm more than happy to dual license it to comply with this Repo's license.