Merged PR 436: 2656 - Implement Optional Negative Reward

## Summary
This PR implements an "ActionPenalty" Reward class, that can be used for penalising an agent when it carries out an action other than DONOTHING.

The value for this can be configured within the scenario YAML file.

## Test process
I've written unit tests to check that the action penalty is correctly calculated and applied, another to check that the config is read correctly and loads into PrimaiteGymEnv correctly.

## Checklist
- [X] PR is linked to a **work item**
- [X] **acceptance criteria** of linked ticket are met
- [X] performed **self-review** of the code
- [X] written **tests** for any new functionality added with this PR
- [ ] updated the **documentation** if this PR changes or adds functionality
- [ ] written/updated **design docs** if this PR implements new functionality
- [ ] updated the **change log**
- [X] ran **pre-commit** checks for code style
- [ ] attended to any **TO-DOs** left in the code

Related work items: #2656

src/primaite/config/_package_data/data_manipulation.yaml

@@ -739,8 +739,6 @@ agents:
           options:
             agent_name: client_2_green_user
 
-
-
     agent_settings:
       flatten_obs: true
 

src/primaite/game/agent/rewards.py

@@ -360,6 +360,38 @@ class SharedReward(AbstractReward):
         return cls(agent_name=agent_name)
 
 
+class ActionPenalty(AbstractReward):
+    """Apply a negative reward when taking any action except DONOTHING."""
+
+    def __init__(self, action_penalty: float, do_nothing_penalty: float) -> None:
+        """
+        Initialise the reward.
+
+        Reward or penalise agents for doing nothing or taking actions.
+
+        :param action_penalty: Reward to give agents for taking any action except DONOTHING
+        :type action_penalty: float
+        :param do_nothing_penalty: Reward to give agent for taking the DONOTHING action
+        :type do_nothing_penalty: float
+        """
+        self.action_penalty = action_penalty
+        self.do_nothing_penalty = do_nothing_penalty
+
+    def calculate(self, state: Dict, last_action_response: "AgentHistoryItem") -> float:
+        """Calculate the penalty to be applied."""
+        if last_action_response.action == "DONOTHING":
+            return self.do_nothing_penalty
+        else:
+            return self.action_penalty
+
+    @classmethod
+    def from_config(cls, config: Dict) -> "ActionPenalty":
+        """Build the ActionPenalty object from config."""
+        action_penalty = config.get("action_penalty", -1.0)
+        do_nothing_penalty = config.get("do_nothing_penalty", 0.0)
+        return cls(action_penalty=action_penalty, do_nothing_penalty=do_nothing_penalty)
+
+
 class RewardFunction:
     """Manages the reward function for the agent."""
 
@@ -370,6 +402,7 @@ class RewardFunction:
         "WEBPAGE_UNAVAILABLE_PENALTY": WebpageUnavailablePenalty,
         "GREEN_ADMIN_DATABASE_UNREACHABLE_PENALTY": GreenAdminDatabaseUnreachablePenalty,
         "SHARED_REWARD": SharedReward,
+        "ACTION_PENALTY": ActionPenalty,
     }
     """List of reward class identifiers."""