Add social links resource and update README with comprehensive documentation

Co-authored-by: ArthurDanjou <29738535+ArthurDanjou@users.noreply.github.com>

server/api/socials.get.ts

@@ -0,0 +1,10 @@
+import { queryCollection } from '@nuxt/content/server'
+
+export default defineCachedEventHandler(async (event) => {
+  return await queryCollection(event, 'socials')
+    .where('extension', '=', 'json')
+    .first()
+}, {
+  name: 'socials-list',
+  maxAge: 3600 // 1 hour
+})