Improved SAC hyperparameters for Crawler, Walker (#2635)

* Tweak SAC hyperparams

* Make network bigger

* Properly report entropy

* Revert "Properly report entropy"

This reverts commit 383a8d8f1d60ee0ef4ffd87a59aa08d974616d4e.

config/sac_trainer_config.yaml

     normalize: true
     time_horizon: 1000
     batch_size: 256
-    train_interval: 3
+    train_interval: 2
     buffer_size: 500000
     buffer_init_steps: 2000
     max_steps: 5e5
     hidden_units: 512
+    reward_signals:
+        extrinsic:
+            strength: 1.0
+            gamma: 0.995
 
 CrawlerDynamicLearning:
     normalize: true
     summary_freq: 3000
-    train_interval: 3
+    train_interval: 2
+    reward_signals:
+        extrinsic:
+            strength: 1.0
+            gamma: 0.995
 
 WalkerLearning:
     normalize: true
     max_steps: 2e6
     summary_freq: 3000
-    num_layers: 3
-    train_interval: 3
+    num_layers: 4
+    train_interval: 2
     hidden_units: 512
     reward_signals:
         extrinsic: