Add ASCIIdoc editor

[Sveino]

In the step to do SchemaOps we should include the possibility to view and edit ASCIIdoc in CIMTool. I do not see that we should build one but add a good existing editor. One example is: https://marketplace.eclipse.org/content/asciidoctor-editor#details

[tviegut]

@Sveino : I worked on the Asciidoc plugin integration and created a simple document to test the PlantUML against the CIMTool Part9 Ed 3.0 Profiles project and generated PlantUML diagrams with the new CIMTool diagrams builder we added in the last release (CIMTool 2.2.0). I also created SVGs from those diagrams within the Part9 project and then in realtime made changes to the profiles (which auto-generates the PlantUML diagrams on save). These then automatically are updated upon refresh in the Asciidoc document making it easy to preview as changes are being made. Here's some screenshots:

This is the PDF generated:

And when I scale the PDF to 250 or greater we obviously retain the fidelity of the UML diagram which we don't get today in jCleanCim for our IEC publications because they are standard images (e.g. PNG) if I recall:

[Sveino]

This is really good news. I am looking forward to test this.