Implement Policy Enforcer Plugin

- Added a new Policy Enforcer plugin to evaluate incoming messages against OPA policies.
- Configurable via YAML with options for policy sources, actions, and query.
- Integrated into existing configuration files for BAP and BPP.
- Updated related tests and documentation for the new functionality.
- Enhanced plugin manager to support Policy Enforcer instantiation.

config/local-beckn-one-bap.yaml

@@ -86,6 +86,12 @@ modules:
           id: router
           config:
             routingConfig: ./config/local-beckn-one-routing-BAPReceiver.yaml
+        policyEnforcer:
+          id: policyenforcer
+          config:
+            policySources: "./policies/compliance.rego"
+            actions: "confirm"
+            query: "data.policy.violations"
         middleware:
           - id: reqpreprocessor
             config:
@@ -93,6 +99,7 @@ modules:
               role: bap
       steps:
         - validateSign
+        - enforcePolicy
         - addRoute
         - validateSchema
   

config/local-beckn-one-bpp.yaml

@@ -84,8 +84,15 @@ modules:
           id: router
           config:
             routingConfig: ./config/local-beckn-one-routing-BPPReceiver.yaml
+        policyEnforcer:
+          id: policyenforcer
+          config:
+            policySources: "./policies/compliance.rego"
+            actions: "confirm"
+            query: "data.policy.violations"
       steps:
         - validateSign
+        - enforcePolicy
         - addRoute
         - validateSchema
   

config/local-simple.yaml

@@ -66,6 +66,12 @@ modules:
           id: router
           config:
             routingConfig: ./config/local-simple-routing.yaml
+        policyEnforcer:
+          id: policyenforcer
+          config:
+            policySources: "./policies/compliance.rego"
+            actions: "confirm"
+            query: "data.policy.violations"
         middleware:
           - id: reqpreprocessor
             config:
@@ -73,6 +79,7 @@ modules:
               role: bap
       steps:
         - validateSign
+        - enforcePolicy
         - addRoute
   
   - name: bapTxnCaller
@@ -162,8 +169,15 @@ modules:
           id: router
           config:
             routingConfig: ./config/local-simple-routing-BPPReceiver.yaml
+        policyEnforcer:
+          id: policyenforcer
+          config:
+            policySources: "./policies/compliance.rego"
+            actions: "confirm"
+            query: "data.policy.violations"
       steps:
         - validateSign
+        - enforcePolicy
         - addRoute
   
   - name: bppTxnCaller