Show iteration list in project iteration page

What does this MR do?

Iterations at a group level has now been released. Issue #222763 (closed) aims to show iterations at project level.

This MR shows an iteration list on the Iteration page in a project by reusing the Iteration components used on the Iteration page in a group.

These changes are behind the feature flag project_iterations, defaulted to off.

This MR is part of a sequence of changes:

1. An MR to add a bare Iterations page in projects (!37715 (merged))
2. An MR to show a list of iterations on the Iterations page in projects (this MR)
3. An MR to show an iteration report within a project (!37979 (merged))
4. An MR to update the iteration GraphQL query, after the backend creates one at the project level

Screenshots

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