Clarification and Proposal to Utilize HealthCheckUrl

[kylepmanuel]

I noticed that the HealthCheckUrl property exists in the configuration but currently seems to be only set and not used. Could you clarify its intended purpose? If the URL is a legacy field or there are no updates planned for its use, I would like to propose the following changes:

1. AddGotenbergHealthCheck: A service collection extension method that integrates with the standard ASP.NET Core health check framework.
2. Optional Pre-Check in GotenbergSharpClient: Add an optional method on GotenbergSharpClient to perform a health pre-check against the HealthCheckUrl before sending any requests. This method will be available for developers to call as needed.

If allowed, I would be happy to implement and submit a pull request for these changes.