Define parsing solution

After build tool and initial structure in place, we next, we need the parsing tool.

For reference, PEG parser was mentioned https://asciidoc.zulipchat.com/#narrow/stream/335219-asciidoc-lang/topic/Austen.20kickoff/near/366291894. @mojavelinux made some of the job for us at https://github.com/opendevise/asciidoc-parsing-lab/tree/main, we can start by trying some Java tools and port some of the features.

As a general goal for this, no need to invest a lot of time, just agree on what to start with and get going.

Any ideas or known projects or experience to begin with?