Improve distributed component documentation
Most of the documentation on antora.yml is written that implies to many readers that there is a 1-1 correspondence between a component-version and an antora.yml. This makes that simple case easy to understand but impedes understanding of distributed components, where several antora.yml files, each found from a sourceURL/start_path/branch-or-tag, specify the same component name and version.
- Since the 1-1 correspondence is only implied, not stated, most of the documentation can remain the same to make understanding the simple, common case easy.
- For a first try, expanding the tip on distributed components might be sufficient.