feat: Add training script for HAPPO algorithm

scripts/train_happo.py

@@ -0,0 +1,15 @@
+import jax
+from mava.algorithms.happo import HAPPO
+from mava.configs.happo_config import HAPPOConfig
+from mava.environments import create_environment
+from mava.trainers import Trainer
+
+def main():
+    config = HAPPOConfig()
+    environment = create_environment(config)
+    algorithm = HAPPO(config)
+    trainer = Trainer(config, environment, algorithm)
+    trainer.train()
+
+if __name__ == "__main__":
+    main()