Covid study 2.1 released with ChatGPT symptom support

[mikix]

The Covid Symptom study now supports ChatGPT 3.5 and 4 symptom extraction from notes.

You can now extract symptom info using the ETL, then format those symptoms into descriptive labels used by the Covid study, then extract those and compare against humans / ICD10 / other NLP with Chart Review.

• covid_symptom__nlp_results_gpt35 (ETL task) -> covid_symptom__symptom_gpt35 (Covid study)
• covid_symptom__nlp_results_gpt4 (ETL task) -> covid_symptom__symptom_gpt4 (Covid study)

See RUNNING.md for more details.