One-button review app creation (backend)

What does this MR do?

This MR adds data related to whether we should show the new Add review app button, onto the Environments page (see #118844 (closed) for more context).

More in detail about what's done here:

• A new ReviewAppSetupSerializer is used in EnvironmentsController to pass the new relevant data.
• Refactoring was done in ProjectPresenter,

Screenshots

From /group/project/-/environments.json

UPDATE: Since this screenshot was taken, the JSON keys have changed. They're now:

can_setup_review_app
all_clusters_empty
review_snippet

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

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 #118844 (closed)