Allow configuring the Instance Level Security Dashboard

What does this MR do?

This MR gives the instance level dashboard the ability to configure the projects.

• New users will see an unconfigured state. They can click on the Add Projects button to configure their dashboard.
• Existing users (also new users) will see an Edit Dashboard button that will bring the user to the project manager to add or remove projects from the dashboard.

Although this is a GQL based component - we had to include the existing project manager which is backed by Vuex and Rest API to deliver the feature on time. The refactoring will be addressed in the upcoming releases.

Screenshots

Here is the demo

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: #214122 (closed)