Add dashboard grid internal component for use with the dashboard layout component

What does this MR do?

This MR adds the grid layout for the Dashboard Layout Component into GitLab UI. In keeping with our aim of having a consistent UI and UX for dashboards at GitLab as outlined by @jiaan in GitLab Dashboard Foundations Roadmap (gitlab-org&18072).

This particular component focuses on the grid layout to be used as an underlying component for the dashboard layout. The dashboard layout does not have any strong opinions on the individual components within a dashboard.

To generate and control the grid layout, we introduce the Gridstack library. Gridstack gives us great control over the dynamic, user editable, grid system. It's been active use for groupoptimize dashboards, as well as the short-lived beta for groupproduct analytics. It's been in the GitLab monorepo for several years now without any major incidents or security concerns. It also is actively maintained with regular releases.

See https://gitlab.com/groups/gitlab-org/-/analytics/dashboards for examples of dashboards using the Vue shared Gridstack wrapper variant originally created by @jiaan.

Screenshots or screen recordings

For use and implementation see: !4556 (merged)

Grid system	Grid system < 768px (md breakpoint)

Integrations

• [-] GitLab: mr_url
• [-] CustomersDot: mr_url
• [-] Duo UI: Update jest config to ignore Gridstack for tran... (gitlab-org/duo-ui!162 - merged)
• [-] Status Page: mr_url
• [-] Docs: mr_url
• [-] Switchboard: mr_url

Does this MR meet the acceptance criteria?

This checklist encourages the authors, reviewers, and maintainers of merge requests (MRs) to confirm changes were analyzed for conformity with the project's guidelines, security and accessibility.

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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

• GitLab UI's contributing guidelines.
• [-] 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.
• [-] Content follows the Pajamas voice and tone guidelines, falling back on the GitLab Documentation Style Guide when needed.
• [-] Related pages are cross-linked, where helpful. Component pages have related components and patterns defined in their Markdown front matter.
• [-] If embedding a Figma file, it follows the Figma embed guide.
• Review requested from any GitLab designer or directly from a maintainer or trainee maintainer.
• Maintainer review follows the Pajamas UX maintainer review checklist.

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] Security reports checked/validated by a reviewer from the AppSec team

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.
  • Static mode - fully navigable via keyboard and screen readers
  • Editing mode - not used right now, but needs work before it is, see Add keyboard support to grid layout (#2885).
• 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.

Related to #2870 (closed)