Section 8. A public officer appointed for any term by the governor, with or without the advice and consent of the council, shall hold his office during the term for which he is appointed and until his successor in office has qualified, unless he is sooner removed in accordance with law. Unless otherwise provided, the beginning of the term of office of a public officer appointed by the governor shall be the date of his appointment, or, if he is appointed by the governor with the advice and consent of the council, it shall be the date of his confirmation; but no officer shall enter upon the duties of his office until he is duly qualified as provided by law.