new feature: add dooray notifier

Dooray! is a cloud-based collaboration solution that integrates and provides essential business services on a single platform, including video conferencing, messaging, project management, email, calendar, and Drive (online file storage).
Dooray Messenger is widely used by private companies and public institutions in South Korea, Japan, and the United States.

Dooray Messenger supports webhooks, allowing integration by generating a hook URL within the service.
We have conducted a one-month test as a Grafana contact point to ensure stability.
To make it more convenient for other customers using Dooray, we aim to add a contact point