Add native health check to connectors

[richard-julien]

Use case

Add health check which validates connection to OpenCTI platform and verifies scheduler is still active

Current Workaround

No

Proposed Solution

Add native healthcheck in the framwork / client python through an option. If this option is activated, depending of the type of the connector, the exposed /health will use a different algorithm to check the health.

Additional Information

We already have an http server starting when activating the metrics / prometheus endpoint. Rely on the same server to prevent starting two different endpoint could be great