Export for the new frameworks report (backend)

What does this MR do and why?

What

Export for the new frameworks report (backend)

• Adds a new endpoint for exporting the new frameworks report
• Emails and sends the report as a CSV
• Behind a feature flag (compliance_frameworks_report_csv_export)

Why

Adds the ability for users to export their frameworks report

Queries database

SELECT "compliance_management_frameworks".* FROM "compliance_management_frameworks" WHERE "compliance_management_frameworks"."namespace_id" = 73

https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/26942/commands/83874

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Email	CSV Attachment

How to set up and validate locally

Setup Frameworks

See: https://docs.gitlab.com/ee/user/group/compliance_frameworks.html#create-edit-or-delete-a-compliance-framework

Note: Ensure frameworks are attached to some projects

Using a group name visit the following below locally

1. Ensure feature flag compliance_frameworks_report_csv_export has been enabled
2. http://gdk.test:3000/groups/group_name/-/security/compliance_framework_reports.csv

Related to #422974 (closed)