Add directory for Stream API

content/stream/stream-api/_index.md

+---
+title: Stream API
+pcx_content_type: overview
+weight: 7
+meta:
+  title: Stream APIs
+---
+
+# Cloudflare Stream
\ No newline at end of file

content/stream/stream-api.md → content/stream/stream-api/stream-api.md

 ---
 pcx_content_type: navigation
 weight: 9
-title: Stream API Reference
+title: REST API Reference
 external_link: https://api.cloudflare.com/#stream-videos-properties
 _build:
   publishResources: false