Move CloudFormation schema file to a GitHub project

[ebekker]

I'm proposing that the CloudFormationV1.schema file be moved over to GitHub under a project, either existing or new, under the AWS org so that it can benefit from community review and contributions.

For example, I have found errors and omissions as described in #38 which could be rapidly corrected by submitting PRs from community members. Accepting these PRs would still be at the discretion of the AWS members who would continue to curate the schema content.

This would help to improve the accuracy of tools that rely on the schema for automated code generation such as:

• aws/aws-toolkit-eclipse
• stevenjack/cfndsl
• ezshield/posh-awscfn
• shalupov/idea-cloudformation

[shalupov]

As the author of CloudFormation support for IntelliJ IDEA I also want to use the schema, but right now it sometimes outdated. Publishing it on GitHub and fixing it there will definitely help.

ref: https://github.com/shalupov/idea-cloudformation