Implement policy system with comprehensive testing and configuration

- Introduced a new policy system for event processing, allowing fine-grained control over event storage and retrieval based on various criteria.
- Added support for policy configuration via JSON files, including whitelists, blacklists, and custom scripts.
- Implemented a test suite for the policy system, ensuring 100% test coverage of core functionality and edge cases.
- Created benchmark tests to evaluate policy performance under various conditions.
- Updated event handling to integrate policy checks for both read and write access.
- Enhanced documentation with examples and usage instructions for the policy system.
- Bumped version to v0.16.0.

app/config/config.go

@@ -54,6 +54,8 @@ type C struct {
 
 	// Sprocket settings
 	SprocketEnabled bool `env:"ORLY_SPROCKET_ENABLED" default:"false" usage:"enable sprocket event processing plugin system"`
+
+	PolicyEnabled bool `env:"ORLY_POLICY_ENABLED" default:"false" usage:"enable policy-based event processing (configuration found in $HOME/.config/ORLY/policy.json)"`
 }
 
 // New creates and initializes a new configuration object for the relay