Create LICENSE CC-BY-SA

[PhilReedData]

Description

• Discussed on Slack, extending Schema.org license. This file is missing.

Motivation and context

• Ensure that a license is available to all users.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New content (non-breaking change which adds new content)
• [ ] Modified content (non-breaking change which modifies existing content)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)