Feat(Analytics/Embedded Insights): add new page

What does this MR do?

This MR adds a new (blank) sibling page to the Analytics Insights page that can be embedded. This will be used to display a single chart from the Insights page that can be embedded into other pages.

This page is behind embed_analytics_report feature flag added here and only works for public groups/projects:

• !35963 (merged)
• !35535 (merged)

Screenshots

Blank screen for now. Does not contain anything yet:

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

To test this out run bin/rake rails c and run the following to activate the feature flag: Feature.enable(:embed_analytics_report, Project.find_by_full_path("Commit451/lab-coat")) Then navigate to http://127.0.0.1:3000/Commit451/lab-coat/insights/embedded to see the page.

Also, to try to embed this into, say the insights page, apply this patch and navigate to http://127.0.0.1:3000/Commit451/lab-coat/insights: test_embedded.patch

Minimal risk since this is behind the feature flag.

• 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

Relates to #224191 (closed)