Add CLI commands for managing webhook endpoints

[gunndabad]

These commands provide a temporary solution for managing webhook endpoints until we have some UI for doing so.

Create an endpoint

> trscli webhook-endpoint create --user-id "0b5b4d7a-f096-493f-aaea-9771fdeaff5c" --address "https://localhost:4200/webhook" --cloud-event-types alert.created alert.updated alert.deleted --api-version Next

{
  "WebhookEndpointId": "e3809f55-71ff-41ff-8a6a-76b4b88219e1",
  "ApplicationUserId": "0b5b4d7a-f096-493f-aaea-9771fdeaff5c",
  "ApplicationUserName": "Developer",
  "ApiVersion": "Next",
  "Address": "https://localhost:4200/webhook",
  "CloudEventTypes": [
    "alert.created",
    "alert.deleted",
    "alert.updated"
  ],
  "Enabled": true
}

List all endpoints

> trscli webhook-endpoint list

[
  {
    "WebhookEndpointId": "e3809f55-71ff-41ff-8a6a-76b4b88219e1",
    "ApplicationUserId": "0b5b4d7a-f096-493f-aaea-9771fdeaff5c",
    "ApplicationUserName": "Developer",
    "ApiVersion": "Next",
    "Address": "https://localhost:4200/webhook",
    "CloudEventTypes": [
      "alert.created",
      "alert.deleted",
      "alert.updated"
    ],
    "Enabled": true
  }
]

Update an endpoint (e.g. disable it)

> trscli webhook-endpoint update --id "e3809f55-71ff-41ff-8a6a-76b4b88219e1" --enabled false

{
  "WebhookEndpointId": "e3809f55-71ff-41ff-8a6a-76b4b88219e1",
  "ApplicationUserId": "0b5b4d7a-f096-493f-aaea-9771fdeaff5c",
  "ApplicationUserName": "Developer",
  "ApiVersion": "Next",
  "Address": "https://localhost:4200/webhook",
  "CloudEventTypes": [
    "alert.created",
    "alert.deleted",
    "alert.updated"
  ],
  "Enabled": false
}

Delete an endpoint

> trscli webhook-endpoint delete --id "e3809f55-71ff-41ff-8a6a-76b4b88219e1"