Prompting and output generation inside Factgenie

[oplatek]

• make the PoC from https://github.com/ufal/factgenie/tree/LLM_generation_feature working
• try it out once we are happy UX
• add 1-2 functional tests to stabilize the UX e.g. configs are saved when creating the campaigns, when launched the calls to the LLM (mocked) servers are done, the progress bar of generation is updated etc