refactor: added reporting_period_start and end attribute to submission_info model#28

stevenhsd merged 2 commits intodevelop_v05NHSDigital/data-validation-engine:develop_v05from

feature/ndit-714_amend_sub_infoNHSDigital/data-validation-engine:feature/ndit-714_amend_sub_infoCopy head branch name to clipboard