Return $metadata resource as odata + openapi spec

Returning odata and openapi specs in json format.
Specs are scoped to the request permissions.
Different users (roles) will receive different metadata endpoints
and resources.

Change-type: minor
Signed-off-by: Harald Fischer <harald@balena.io>

Author: fisehara

package.json

@@ -56,7 +56,8 @@
     "memoizee": "^0.4.15",
     "pinejs-client-core": "^6.10.0",
     "randomstring": "^1.2.2",
-    "typed-error": "^3.2.1"
+    "typed-error": "^3.2.1",
+    "odata-openapi": "^0.12.0"
   },
   "devDependencies": {
     "@balena/lint": "^6.2.0",