Revert "Issue #2033211 by LewisNyman, tim.plunkett, JamesLefrère | yannickoo: Move Seven CSS files into css directory."

This reverts commit 16e60c421b49632d3ca65664a94b44bd20703dc1.
Issue #2302843 by claudiu.cristea: {cache_tags} conflicts with cache bin database table names.
Issue #2303547 by mgifford: Fixed Consistency - screen-reader to screen reader.
Issue #2301955 by er.pushpinderrana, lokapujya | scor: Ensure RDFa metadata tags are hidden.
Merge remote-tracking branch 'origin/8.x' into mink-testing-2232861-green