Implements component to render maven upstream details

What does this MR do and why?

This change introduces a new component for displaying Maven upstream details in the virtual registries feature.

The component shows information about a Maven upstream registry, including its name, description, URL, and cached artifacts. The UI displays a title area with metadata about the registry type and artifact count, followed by a search filter and a table to view artifacts.

The component is standalone currently since the backend API & routes are being implemented. I've added a story so that we can continue iterating on the designs.

References

• Design: #493842[Cache-entries.png]

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. cd storybook
2. yarn start
3. Visit http://localhost:9002/?path=/story/ee-virtual-registries-maven-upstream-details--default

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Related to #526734 (closed)