Add mandatory and recommended files to website repository

All mandatory and recommended files are missing from your website repository. Please add them at your earliest convenience.

Required files:

• License files in all repository roots
• README
• CONTRIBUTING (or equivalent)

Recommended files:

• NOTICES or equivalent (you can use the Legal Documentation generator available under committer tools)
• CODE_OF_CONDUCT
• SECURITY

See examples for Security file and Code of Conduct.