Add node topic to KNIME help

[sverhoeven]

In KNIME in menu Help -> Help Contents -> KNIME -> Node Descriptions, there are topics for all the nodes. Except nodes generated with this archetype, they are not listed.

[sverhoeven]

The extension org.eclipse.help.toc from the org.eclipse.help bundle must be used to add topics to the help.

[sverhoeven]

The https://github.com/3D-e-Chem/knime-3d-e-chem plugin should have a toc 3D-e-Chem which links to ../org.knime.workbench.help/toc.xml#node-descriptions". Then nodes of the project can be nested under this toc.

[sverhoeven]

On https://www.knime.com/blog/creating-knime-update-sites-with-buckminster chapter Node descriptions in online help there is a reference to a buckminster script which can generate the help files from the manifest.

The buckminster script runs an actor class (org.knime.build.actors.DocBuilderActor) which can be found in the org.knime.build plugin.

[sverhoeven]

It would be nice if we could build the docs using a mvn command which than makes it part of the plugin.jar