Overview and glossary/dictionary of buildstream terms/meanings

AFAIK there isn't any reference to explain the special concepts/words/terms bst for new users, e.g.:

• artifact
• cache
• junction
• element
• sandbox

Some of the technical documentation almost covers it, e.g. https://buildstream.gitlab.io/buildstream/buildstream.element.html

But I think we need to separate out (s) at the top-level some introductory guide to the architecture, concepts and special words. Some of this content could usefully be distilled from Tristan's original blog posts and presentations, for example.

So my suggestion would be that the top level documentation page gains links to one or more additional section(s) covering overview, key concepts and glossary.