add different plot types

Step 1: 
Added PlotType enum and a drop down to the UI.
Extracted the code for scatter plots.

data-store/src/main/java/org/lucares/pdb/datastore/internal/DataStore.java

@@ -260,10 +260,6 @@ public class DataStore {
 	
 				final Doc doc = docIdToDoc.get(docId);
 				
-				if (!doc.getTags().getValue("pod").equals("vadtrans01")){
-					System.out.println();
-				}
-				
 				result.add(doc);
 			}
 		}