[FEATURE] Show thumbnails in page/list by default

Improve defaults for new backend users by showing thumbnails.
Displays thumbnails in page/list module by default.

Change-Id: Icb339df19ff7f75b4af1af5ae35928eb2d059270
Fixes: #32893
Releases: 4.7
Reviewed-on: http://review.typo3.org/7641
Reviewed-by: Fabien Udriot
Tested-by: Fabien Udriot
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Tomita Militaru
Tested-by: Tomita Militaru
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer