[RLlib] Deprecate all Model(v1) usage. (#8146)

Deprecate all Model(v1) usage.

rllib/BUILD

@@ -1406,7 +1406,7 @@ py_test(
     name = "examples/nested_action_spaces_ppo",
     main = "examples/nested_action_spaces.py",
     tags = ["examples", "examples_N"],
-    size = "small",
+    size = "medium",
     srcs = ["examples/nested_action_spaces.py"],
     args = ["--stop=-500", "--run=PPO"]
 )

rllib/agents/ars/ars_tf_policy.py

@@ -36,15 +36,18 @@ def __init__(self, obs_space, action_space, config):
         dist_class, dist_dim = ModelCatalog.get_action_dist(
             self.action_space, config["model"], dist_type="deterministic")
 
-        model = ModelCatalog.get_model({
-            SampleBatch.CUR_OBS: self.inputs
-        }, self.observation_space, self.action_space, dist_dim,
-                                       config["model"])
-        dist = dist_class(model.outputs, model)
+        self.model = ModelCatalog.get_model_v2(
+            obs_space=self.preprocessor.observation_space,
+            action_space=self.action_space,
+            num_outputs=dist_dim,
+            model_config=config["model"])
+        dist_inputs, _ = self.model({SampleBatch.CUR_OBS: self.inputs})
+        dist = dist_class(dist_inputs, self.model)
+
         self.sampler = dist.sample()
 
         self.variables = ray.experimental.tf_utils.TensorFlowVariables(
-            model.outputs, self.sess)
+            dist_inputs, self.sess)
 
         self.num_params = sum(
             np.prod(variable.shape.as_list())