What (a) total number of foreign educated and trained persons in the medical field, by category of medical profession, who either return or come to the Republic seeking to become registered and/or employed within the public health service, (i) have applied to write the required examinations to become qualified and (ii) were rejected and (b) were the reasons for such rejection in the (i) 2020, (ii) 2021 and (iii) 2022 academic years?