feat(cms): add management for partnerships, history, accreditation, admissions, and policies pages

Implement a singleton page content system to manage static informational pages. This includes:
- New controllers, models, and data files for Partnerships, History, Accreditation, Admissions, and Policies.
- Admin routes and views for updating page content.
- Public API endpoints for fetching page data.
- Migration scripts for initializing page data.
- Updated admin navigation layout to include a dropdown for "About" sections.
- Audit action constants for tracking updates to these pages.

models/accreditationPage.js

@@ -0,0 +1,7 @@
+const createSingletonPageModel = require("./_createSingletonPageModel");
+
+module.exports = createSingletonPageModel(
+  "AccreditationPage",
+  "accreditation_pages",
+  "accreditation",
+);