LMS-1483 Further work on the graph/plot framework.

screening/etc/service.properties

screening/etc/tabular-data-graph.properties

...d/openbis/dss/generic/server/TabularDataGraphServlet.java

...is/dss/generic/server/graph/AbstractTabularDataGraph.java

...d/openbis/dss/generic/server/graph/ITabularDataGraph.java

...server/graph/TabularDataGraphCollectionConfiguration.java

...s/generic/server/graph/TabularDataGraphConfiguration.java

...s/dss/generic/server/graph/TabularDataGraphGenerator.java

.../openbis/dss/generic/server/graph/TabularDataHeatmap.java

...ric/server/plugins/ImageAnalysisGraphReportingPlugin.java

...nbis/dss/generic/server/graph/TabularDataHeatmapTest.java