Update Documentation

[monicagrimley]

• Reorganize the get started to foreground the dev get started guide
• Finish the release notes so that we can show individual release note pages and link directly to them
• Rewrite the CLI reference to include the latest commands and flesh out the docs
• Update the integration guide to support the new integration flags and options added in 14.1
• Document snippets, how to use them, why to use them, etc.
• Document MDX support, both in the CLI and in the developer or documentation sections