Health check for non-web services

[nijel]

Describe the problem

Currently, the health check is focused on the web only. When WEBLATE_SERVICE is configured to something else, it doesn't work because it looks for the web server.

Describe the solution you would like

Make https://github.com/WeblateOrg/docker/blob/main/health_check look for the actual service being executed in the container.

Describe alternatives you have considered

No response

Screenshots

No response

Additional context

No response