Add Loki and Sentinel utility classes for web API endpoints

- Implemented LokiUtils class with GET and POST endpoints for managing scripts, jobs, and payloads.
- Added SentinelUtils class with GET and POST endpoints for managing events, rules, devices, and notifications.
- Both classes include error handling and JSON response formatting.

loki/payloads/hello_world.js

@@ -0,0 +1,9 @@
+// Hello World — Test payload that types a message in Notepad (Windows)
+layout('us');
+delay(1000);
+press("GUI r");
+delay(500);
+type("notepad\n");
+delay(1000);
+type("Hello from Bjorn Loki!\n");
+type("HID injection is working.\n");