Rego Policy Improvements

[pickjasmine]

Look into adding syntax highlighting wherever we show rego policy code

Links from Robert:
https://prismjs.com/
https://jcguest90.medium.com/reacttext-editor-with-syntax-highlighting-9ae15d93cac0
https://www.npmjs.com/package/react-simple-code-editor?activeTab=readme

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Add a "Hello World" policy that outlines our expectations of a policy to get people started.

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Improve styling of errors that are returned when validating a policy. Currently they are just one big line of the array of errors, but this could be styled to be easier to read.