refs #5940 splitting plugin tests folder into unit, integration and system for now

plugins/API/tests/Integration/RowEvolutionTest.php

plugins/API/tests/Integration/RssRendererTest.php

plugins/API/tests/Unit/ConsoleRendererTest.php

plugins/API/tests/Unit/CsvRendererTest.php

plugins/API/tests/Unit/HtmlRendererTest.php

plugins/API/tests/Unit/JsonRendererTest.php

plugins/API/tests/Unit/OriginalRendererTest.php

plugins/API/tests/Unit/PhpRendererTest.php

plugins/API/tests/Unit/XmlRendererTest.php

plugins/Actions/tests/Unit/ArchiverTest.php

plugins/Contents/.gitignore

plugins/Contents/tests/System/ContentsTest.php

...nts.getContentNames_lastN__API.getProcessedReport_day.xml

...ts.getContentPieces_lastN__API.getProcessedReport_day.xml

...ystem/expected/test_Contents__Actions.getPageUrls_day.xml

...tem/expected/test_Contents__Actions.getPageUrls_month.xml

.../tests/System/expected/test_Contents__Actions.get_day.xml

...ests/System/expected/test_Contents__Actions.get_month.xml

.../expected/test_Contents__Contents.getContentNames_day.xml

...xpected/test_Contents__Contents.getContentNames_month.xml