Awesome Copilot collection (#360)

* Adding a collection for the meta prompts to help discover items in the awesome copilot repo

* Forgot to run validation locally

* YAML schema validation set and updating readme

.vscode/settings.json

@@ -13,5 +13,8 @@
     "*.chatmode.md": "markdown",
     "*.instructions.md": "markdown",
     "*.prompt.md": "markdown"
+  },
+  "yaml.schemas": {
+    "./.schemas/collection.schema.json": "*.collection.yml"
   }
 }