[TASK] Replace legend.png with CSS/HTML

Replace legend.png from Access module with
a CSS/HTML replacement.
follow up for #63245

Resolves: #63245
Releases: master
Change-Id: I64575469ab03e4278d4c26c1427c8c14e1e60d7e
Reviewed-on: http://review.typo3.org/34713
Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>