Add Docker container image and automate uploads to GitHub Container Registry

[abeckDev]

Task:

• Create a Dockerfile for the project in the repository that builds a container image for DB-TimetableAPI-MCPServer.
• Set up a GitHub Actions workflow that builds the Docker image whenever changes are pushed to the main branch.
• Automate the publishing of the Docker image to the GitHub Container Registry associated with this repository upon successful builds on the main branch.

Requirements:

• Ensure the Dockerfile is optimized for the app, including copy/install steps for all dependencies and build artifacts as appropriate.
• Properly tag the image (preferably using the commit SHA or semantic versioning that matches repo conventions).
• Securely use GitHub secrets for registry authentication in the workflow.
• Document the usage and workflow in the README (overview of build, push, and usage).

Acceptance Criteria:

• Repository contains a valid Dockerfile for the app.
• An automated workflow (GitHub Actions) is triggered on changes to main and uploads the container to GitHub Container Registry.
• Uploaded images are accessible and properly tagged.
• Documentation is updated to show how the container is built, tagged, and published.