Add CSM ruleset

[zmackie]

What does this PR do?

Creates a ruleset for CSM markdown

Motivation

Frequent errors (on my part) that could be automated away

Release

Not sure?

• [ ] YES, this PR requires a release
• [ ] NO, this PR doesn't need a release

Additional Notes

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Release checklist

• [ ] Create zip files for EACH style folder.
• [ ] Attach the zip files when creating a release.