Small enhancement of AsciiDoc features

[MichaelHoffmeisterFesto]

This branch brings small enhancement of AsciiDoc features:

• add a heading4 semanticId to allow deeper nested
  Submodel templates
• add the ability for directory structures to be zipped
• add the UI option to produce AsciiDoc for Antora
  (special directory structure)
• arrange files in special directory structure
• add a view post command to AsciiDoc, together with a
  small keyboard macro in the options, the currently
  edited SMT could be viewed immedeatily without
  any script file
• replace the CountryFlags nuget with code already
  used by the BlazorExplorer project

This is the keyboard macro (in src/AasxPackageExplorer/options-debug.MIHO.json):

{
      "Name": "AsciiDoc - Export and view  (Ctrl+Shift+8)",
      "Lines": [
        "Tool(\"LocationPush\");",
        "Select(\"Submodel\", \"First\");",
        "Select(\"Submodel\", \"Next\");",
        "Tool(\"ExportSmtAsciiDoc\", \"File\", \"C:\\Users\\homi0002\\Desktop\\tmp\\new.zip\", \"ExportHtml\", \"true\", \"ExportPdf\", \"false\", \"AntoraStyle\", \"false\", \"ViewResult\", \"true\");",
        "Tool(\"LocationPop\");"
      ]
}