add reference material for submit.yml.erb back

[johrstrom]

https://osc.github.io/ood-documentation-test/submit-yml-docs/

reference documentation for submit.yml.erb was oringially added in #385 (sans script documentation) then removed in #696 for what I can only suspect was my preference for the ruby docs.

while maintaining 2 separate documentation pages (ruby docs on ood_core and this) is not spectacular - I'm not sure there's a viable alternative as the ruby docs are hard to read (or discover) for most users.