feat: coreference resolution

[fynnos]

This PR adds SOTA coreference resolution for German to DATS including

• German maverick packaged as pip package
• Model uploaded to hf hub
• new ray model worker endpoint
• updated ray dependencies to support the coref model (esp. PyTorch, transformers)
• Coref service to use the endpoint
• ML job of type coref
• special annotation display for coreferences (without any code name) and colors based on the groups instead of code id
• button to start coref ML job