Implement pattern state lowest common denominator

[bmuenzenmeyer]

While reviewing documentation, I realized I never fully finished the pattern state implementation.

Any pattern that includes a pattern partial that has a lower pattern state will inherit that state. For example, a pattern with the state of inreview that includes a pattern partial with the state of inprogress will have its state overridden and set to inprogress. It will not change to inreview until the pattern partial has a state of inreview or complete.

Code reference: https://github.com/pattern-lab/patternlab-php-core/blob/c2c4bc6a8bda2b2f9c08b197669ebc94c025e7c6/src/PatternLab/PatternData/Helpers/PatternStateHelper.php