Update Danger roulette

What does this MR do?

Update Danger roulette

This adds a new roulette Dangerfile that's based on GitLab's version: https://gitlab.com/gitlab-org/gitlab/-/blob/3dc8a1385eb15ab9a950c6b966803a5167d7c9ca/danger/roulette/Dangerfile

This removes various things we don't need, and relies entirely on code owners.

Part of #2034 (closed).

Use group for catch-all code owners section

Since psimyn is a frontend maintainer, this was redundant.

Remove code owners section without owners

The UX trainee maintainers section had no owners, so it was useless.

Don't suggest engineer review for docs changes

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Integrations

• GitLab: mr_url
• CustomersDot: mr_url
• Duo UI: mr_url
• Status Page: mr_url
• Docs: mr_url
• Switchboard: mr_url

Does this MR meet the acceptance criteria?

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Conformity

• The “What does this MR do?” section in the MR description is filled out, explaining the reasons for and scope of the proposed changes, per “Say why not just what”.
  • For example, if the MR is focused on usage guidelines, addressing accessibility challenges could be added in a separate MR.
• Relevant label(s) are applied to the MR.
• The MR is added to a milestone.
• Added the ~"component:*" label(s) if applicable.

Components

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• If the MR changes a component's API, integration MR(s) have been opened (see integrations above).

Documentation

• If creating a new component page from scratch, it follows the page template structure.
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• Related pages are cross-linked, where helpful. Component pages have related components and patterns defined in their Markdown front matter.
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• Maintainer review follows the Pajamas UX maintainer review checklist.

Security

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Accessibility

If this MR adds or modifies a component, take a few moments to review the following:

• All actions and functionality can be done with a keyboard.
• Links, buttons, and controls have a visible focus state.
• All content is presented in text or with a text equivalent. For example, alt text for SVG, or aria-label for icons that have meaning or perform actions.
• Changes in a component’s state are announced by a screen reader. For example, changing aria-expanded="false" to aria-expanded="true" when an accordion is expanded.
• Color combinations have sufficient contrast.