[BUGFIX] Remove Verdana, Helvetica and Arial from default site

This removes the explicit fonts from the default site and displays
the text in the default "sans-serif" font the browser uses.

Resolves: #75769
Releases: master
Change-Id: Ib5b4c4d22ac0d55033110b8aa6740c6f837b71f2
Reviewed-on: https://review.typo3.org/47772


Reviewed-by: Nicole Cordes <typo3@cordes.co>
Tested-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Christoph Kratz <ckr@rtp.ch>
Tested-by: Christoph Kratz <ckr@rtp.ch>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>