Mobile: Reduce fontsize

Page: Homepage [https://typo3.org/]

Issue: We found that at many places there is bigger font as compared to normal in responsive view, we would suggest making the smaller font in mobile view to look site proper and to avoid horizontal scrollbar.

Screenshot: http://prntscr.com/j8uxo4, http://prntscr.com/j8uxxj, http://prntscr.com/j8w31x