Use uv project manager & gitlab CI

• switches the wmfdata project to using uv as package manager
• add blubber definition for wikimedia deployment pipeline
  • development variant for an image that install all system and project dependencies
  • juptyer variant (e.g. could be used on DSE cluster)
• add gitlab ci yaml
  • uses the blubber variant development as base image for all jobs
  • jobs for linting / type checking / tests
    • all these jobs fail, for now allow-failure is true
  • job for publishing a packaged environment to the package registry
• no logical changes to the code, which has moved to the src directory
• add development notes for updated structure
• all code files have been formattted

Note that gitlab ci is set to allow failure for formatting, type checking and unit testing for now.