Draft: Implement @nuxt/content v3

1. Change Summary

[Describe what is changing, why, and the impact]

• Closes: #342

2. QA Checklist

[This merge request should follow all best practices utilizing our team code standards and our project's development documentation]

• Code Cleanup: Any messages, linter warnings, and/or deprecation warnings are cleaned up in the console
• Tech Debt: I have created, or documented, any fast follow-up work that needs to be done after this MR is merged
• Efficient Code Review: I have tested and reviewed my own changes thoroughly before assigning a reviewer
• Accessibility: Axe tools run and issues addressed
• Cross-browser compatibility: Works on Safari, Chrome, and Firefox
• Analytics and SEO: Compatible with Google Analytics and SEO tools
• Localization checked for regressions

[Provide concise steps to test the changes]

Review App

Production	Review app
https://about.gitlab.com/	https://content-v3.about.gitlab-review.app/platform/

3. Deployment Steps

[List key deployment steps or configurations]

content.config.ts

@@ -30,6 +30,18 @@ export default defineContentConfig({
         include: '**/blog/authors/*.yml',
         prefix: '/',
       },
+      schema: z.object({
+        content: z.object({
+          name: z.string(),
+          config: z.object({
+            headshot: z.string().optional(),
+            ctfId: z.string()
+          })
+        }),
+        config: z.object({
+          template: z.string()
+        })
+      })
     }),
 
     // Blog Categories