[TASK] Show 'styles' object in TypoScript Object Browser

When you look in the TOB for the styles.* settings, those are not
shown. In order to ease the lookup of existing settings, let's
show them there.

Resolves: #60567
Releases: 6.3
Change-Id: I5163736c21847070c50e29911fff2b492f7cfc87
Reviewed-on: http://review.typo3.org/31814
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>