Add Update Wizards for Skinning Changes
- Check for $TYPO3_CONF_VARS[BE][compressionLevel] active and warn user to include the lines from misc/advanced.htaccess
- Check for having EXT:t3skin installed and warn user to install it or another 4.4 compatible skin
Both wizards are sufficient, if they simply warn the user that it will result in a broken backend otherwise.
I corrected the version
(issue imported from #M14752)