Nginx Healthcheck endpoint + Dockerfile healthcheck

[tarampampam]

Description

Previous PR updates

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I wrote unit tests for my code (if tests is required for my changes)
• I have made changes in CHANGELOG.md file

[tarampampam]

@modem7 could you please review these changes?

[modem7]

I'd say the healthcheck period is a bit too short, 10-20 seconds is definitely sufficient for this type of container. It may cause false positives if its too quick.