Review all sniffs for compatibility with PHPCS >= 4.0

Development on PHPCS 4.x has started a while back.

While there is no timeline known for when it will be ready/released, some (breaking) changes which PHPCS 4.x will contain are already known.

Notable changes as known at the time of writing this:
* The minimum supported PHP version is slated to become PHP 7.2.
* Support for the PEAR installation method will be removed.
* Support for JS and CSS sniffs will be removed.
* Support for the "old-style" ignore annotations, like `@codingStandardsIgnoreLine` will be removed. These were deprecated in PHPCS 3.2.0.
* Support for the "old-style" array properties in rulesets, where array items would be passed via a comma separated value instead of as individual items. This was deprecated in PHPCS 3.3.0.
* Deprecated tokens will be removed, most notably `T_ARRAY_HINT` and `T_RETURN_TYPE` which were both deprecated in PHPCS 3.3.0.

I expect most of this won't have much effect on the sniffs in VIPCS. If/when more changes become known, I will update the above list.

However, a decision is needed about the future of the sniffs which look at JS/CSS code. There is no urgency (yet), but I'm opening this issue now to raise awareness and open the discussion about this.

Es sind keine bestimmten Dateien oder Tests genannt. Beginne damit, alle VIPCS-Sniffs anhand der aufgeführten Änderungen in PHPCS 4.x zu überprüfen, und untersuche anschließend die Diskussion darüber, ob die JavaScript- und CSS-Sniffs entfernt oder beibehalten werden sollen. Als erledigt gilt die Aufgabe, wenn die Kompatibilitätsfeststellungen dokumentiert und eine Entscheidung zu den betroffenen Sniffs getroffen wurde.

Vom Indexierungsmodell aus dem Issue-Text verfasst.