MTDE Data Elements Updated

• Renamed the field to treatment.complete_resection_clear_margins
• Removed tumor_grade and moved its values and description into the cancer_grade description
• Added case.days_to_sample_collection.
• Renamed index_date to index_event
• Updated tobacco exposure values to use clear string values instead of numeric ranges (1–7)
• Changed gender to sex.
• Fixed some descriptions and spelling mistakes (Prometheus)