Backend: Modify Secure Configuration page to provide data for enabling SAST job

Problem to solve

Provide additional information in @configuration param so that the page described in the issue can be rendered.

Implementation Plan

• Expose information about whether a CI file exists in @configuration param of the controller
• Expose information about whether ADO is enabled in @configuration param of the controller
• Expose REST endpoint for MR creation flow (see #227048 (closed) and/or #223878 (closed)) as create_sast_merge_request_path
• Provide path/url to ADO enablement page.
• Work on https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/controllers/projects/security/configuration_controller.rb#L20