ExDM External Data Management PR to master and delete the branch #396

- working on: Update the doc folder

ExDM Add documentation to the selected parts of the code #369

- working on the XAML section

ExDM Add documentation to the selected parts of the code #369

- working on the MVVM in the README.MVVM.md document - finished first attempt

ExDM Add documentation to the selected parts of the code #369

- Working on GraphicalData

ExDM Add documentation to the selected parts of the code #369

- Working on StructuralData

ExDM Add documentation to the selected parts of the code #369

- Working on StructuralData

ExDM Add documentation to the selected parts of the code #369

Reviving READMESerialization.md - working on links to local sections

ExDM Add documentation to the selected parts of the code #369

- working on DataStreams
- fixed typo in FileStreamUnitTest.cs
- backup copy

ExDM Add documentation to the selected parts of the code #369

- working on the ExDataManagement/READMECryptography.md
- backup commit

ExDM Add documentation to the selected parts of the code #369

reviewed DataStreams/DataStreams/README.md
ready to publish 231231-PiP-ExternalDataFileStreamConcepts\Manuscript.md