Update backend page title
Since the introduction text of the install tool has been updated recently for 6.2 I think it is about time the page title of the backend is also updated to reflect the brand change. Thus "TYPO3 <version>" becomes "TYPO3 CMS <version>".
[TASK] Update backend page title
Updates the document title in backend following the brand change
from TYPO3 to TYPO3 CMS