Refactor DiscordGateway2HttpMaster to Maven Project Structure

[moflwi]

What

The current code structure in the Dockerfile is not following best practices and is considered an anti-pattern. The comment # this is super anti-pattern, fix with a proper maven project suggests that the project should be refactored to adhere to a proper Maven project structure.

Where

https://github.com/plengauer/Philbot/blob/main/DiscordGateway2HTTPMaster/Dockerfile#L4

Acceptance Criteria

• The Dockerfile should reflect the updated Maven project structure.
• The project should build and run successfully with the new Maven structure.
• The maven project should work seamlessly with Renovate.

[github-actions]

Hello, thanks for adding an issue for the first time!

[plengauer]

I think another requirement should be that it will work with renovate (including a manual version bump thats in the github actions similar to the one for the scheduler, i.e., if a maven dependency is updated, a commit must be added to the PR bumping the minor version. see https://github.com/plengauer/Philbot/blob/main/.github/workflows/bump_version_scheduler.yml)