Add support to change FireHydrant settings

[WarrDoge]

Use-cases

We would like to configure automatic incident webhooks using IaC. We want to be able to set an endpoint, incident scope and HMAC secret. It is not related to Runbook webhooks.

Proposal

resource "firehydrant_settings_webhooks" "my_automatic_webhook" {
    url = "https://someurl.com"
    secret = "some_secret"
    status = "active"
    event_subscriptions = [
      "Change Events",
      "Incidents",
      "Incidents (private)"
    ]
}