stages/cloud-init: add support for configuring reporting handlers

It's possible the keys "logging" and "telemetry" can be arbitrary names.
If that's the case, we can change the schema without breaking backwards
compatibility, so defining known keys is safer.

stages/org.osbuild.cloud-init

@@ -24,6 +24,12 @@ import osbuild.api
 
 
 SCHEMA = r"""
+"definitions": {
+  "reporting_handlers": {
+    "type": "string",
+    "enum": ["log", "print", "webhook", "hyperv"]
+  }
+},
 "additionalProperties": false,
 "required": ["config", "filename"],
 "properties": {
@@ -58,6 +64,32 @@ SCHEMA = r"""
           }
         }
       },
+      "reporting": {
+        "type": "object",
+        "additionalProperties": false,
+        "description": "Define reporting endpoints.",
+        "minProperties": 1,
+        "properties": {
+          "logging": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "type": {
+                "$ref": "#/definitions/reporting_handlers"
+              }
+            }
+          },
+          "telemetry": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "type": {
+                "$ref": "#/definitions/reporting_handlers"
+              }
+            }
+          }
+        }
+      },
       "datasource_list": {
         "type": "array",
         "items": {