Cloudformation resource schema

[benbridts]

Here are some examples of things that are a good idea to check in CloudFormation Resource schemas.

I moved the other examples around to have a place to put them

Opening as a WIP, so feedback can be given about structure / rules

Todo:

• writing tests
• I want to move tests to a different folder (so that cfn-guard validate --rules cloudformation-resources/ doesn't;t throw an error), but I'll probably do that in separate pull request

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