improve readability of code

* coding style fixes
* some PHPStorm code inspection fixes
* few method extractions
* removed unused methods
* whitespace fixes

 all as part of our code cleanup strategy and to make code better readable.
The variables names and getters are redundant. If you consider this line too big, maybe you do this:
<pre>return Rules::getMinTimeProcessedForTemporaryArchive(
            $this->params->getDateStart(),
            $this->params->getPeriod(),
            $this->params->getSegment(),
            $this->params->getSite()
        );</pre>