Replace ApplicationRunner with EventListener to fix startup time

[GODrums]

Motivation

Guarantee the Github sync only runs after the server has started and is available.

Description

Replaces the ApplicationRunner with an EventLister for the ApplicationReadyEvent event.

Checklist

General

• PR title is clear and descriptive
• PR description explains the purpose and changes
• Code follows project coding standards
• Self-review of the code has been done
• Changes have been tested locally

Server (if applicable)

• Code is performant and follows best practices
• No security vulnerabilities introduced
• Proper error handling has been implemented
• Added tests for new functionality
• Changes have been tested in different environments (if applicable)

[FelixTJDietrich]

LGTM Thanks!