Add ability to use GraphQL for QA resource creation

What does this MR do?

This MR adds the ability to use GraphQL instead of the REST API for creating QA resources. It also updates the iteration resource creation to utilize this new functionality.

While working on this, it turns out there’s no rest api endpoint for iterations but instead it uses GraphQL. I've modified the code as little as possible just to see if it will work with GraphQL but I would like some feedback on how it can be implemented a bit cleaner, perhaps with a GraphQL Client.

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

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• 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
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