[Docs] Add wiki content to Markdown docs Change-Id: I729d3208b206e83f99e73002b45402c4f6f9f443 Reviewed-on: https://chromium-review.googlesource.com/301560 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>