Rudder

Add an API to get all hooks in order to create hook's page
The format should look like :

{
  "action": "listHooks",
  "result": "success",
  "data": {
    "root": "/opt/rudder/etc/hooks.d",
    "events": {
      "node-inventory-received-accepted": [],
      "node-inventory-received-pending": [],
      "node-post-acceptance": [],
      "node-post-deletion": [],
      "node-pre-deletion": [],
      "policy-generation-failed": [],
      "policy-generation-finished": [],
      "policy-generation-node-finished": [],
      "policy-generation-node-ready": [],
      "policy-generation-started": [],
    }
  }
}