Add basic components for packages settings

What does this MR do?

This MR adds some basic components to build the new settings UI described in the issue, this work is behind feature flag

The Plan

Feature flag rollout issue: #297371 (closed)

Step	MR
Add new page and menu entry + feature flag	!51460 (merged)
Add basic components + queries and mutations	👈 you are here!
Wire the new UI and UX review	TBD
Document + remove feature flag	TBD

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Related to #296895 (closed)