This patch backports a golang program that generates RPC help markdown from bitcoind.
Minor changes were made to accommodate assumptions made by Jekyll. No indexing, styling, or other
improvements have been made yet. These will come in following diffs.
I did not include the generated docs in this diff either, as some follow-up diffs will make
modifications that change all of the generated docs. I will commit them to source control when
it makes sense to do so.
Depends on D6589 for config maintenance.