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

IEC-61131 PLC programming
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Contents:

.. toctree::
   :maxdepth: 2

   create
   configuration
   edit
   connect
   run
   stdlib/index