Extend HMI:JsonTable, create Edit CSV POU, create example, add some doc (#41)

* Extend Jsontable widget, create Edit CSV POU, create example for both

* Add doc for HMI:Image and HMI:JsonTable

* Expand example to include HMI:Image

                  <xsd:element name="Generic">
                    <xsd:complexType>
                      %(toolchain_makefile)s
                    </xsd:complexType>
                  </xsd:element>