Removing deprecated Advanced Syntax Highlighting

Advanced syntax highlighting causes errors when trying to save code in the SCB but does not provide any benefits because the ACE editor has its own syntax highlighting. To clean up old deprecated and broken code from Lively, this pull requests removes the "Advanced Syntax Highlighting".

Maybe it would be good to remove the old legacy syntax highlighting in ``core/lively/ide/SyntaxHighlighting.js`` as well and depend completely on ACE. This would reduce the amount of code and thereby the work needed to maintain it.