updated version of application RetrievalTrainer:  1.0.4
updated version of application RetrievalTrainer:  1.0.4

removed maven assembly plugin ( because of jpackage tool in java 14 )

included javafx maven plugin

added maven dependencies for "javafx-controls" and "javafx-fxml"

updated maven compiler plugin and maven jar plugin

cleanup of pom.xml

DGHerm/RetrievalTrainer,DGHerm/RetrievalTrainer