Allow partial specification for deeply nested inventories

For objects that are not simple attributes of the resource (i.e.
objects, lists) allow specifing subset of values that needs to be
verified.

In case of lists, count of list objects must match, but if values are
objects / dicts, they can be specified as empty dicts which should pass
all the checks, as no keys are specified.

tests/modules/cloud_function_v2/examples/secrets.yaml

@@ -16,14 +16,7 @@ values:
   module.cf-http.google_cloudfunctions2_function.function:
     name: test-cf-http
     service_config:
-      - all_traffic_on_latest_revision: true
-        available_cpu: '0.166'
-        available_memory: 256M
-        environment_variables: null
-        ingress_settings: ALLOW_ALL
-        max_instance_count: 1
-        min_instance_count: 0
-        secret_environment_variables:
+      - secret_environment_variables:
           - key: VARIABLE_SECRET
             project_id: '1234567890'
             secret: var_secret
@@ -39,9 +32,7 @@ values:
                 version: '2'
               - path: latest
                 version: latest
-        timeout_seconds: 180
-        vpc_connector: null
-        vpc_connector_egress_settings: null
+
 counts:
   google_cloudfunctions2_function: 1
   google_storage_bucket_object: 1