Add issues_statistics api endpoints

What does this MR do?

Changes to issues api

When issues_controller endpoint was used for search, the parameters passed to the controller were slightly different then the ones passed to API. Because the searchbar UI is reused in different places and builds the parameters passed to request in same way we need to account for old parameter names.

Add issues_statistics api endpoints

Adds issue_statistics api endpoints for issue lists and returns counts of issues for all, closed and opened states.

Expose more label attributes based on a param

When requesting issues list through API expose more attributes for labels, like color, description if with_labels_data param is being passed, avoiding this way to change response schema for users that already use API.

https://gitlab.com/gitlab-org/gitlab-ce/issues/57402

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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