AURORA-234: Replace HTML tables in docs with markdown

Testing Done:
Generated the Aurora site using Middleman. Everything renders correctly, though I've updated the Jira ticket with a comparison between the two rendered tables.

Commit on Github: https://github.com/protochron/incubator-aurora/commit/558a5a6a2f15a82e51ef7bf6d17288f67ff11a97

Bugs closed: AURORA-234

Reviewed at https://reviews.apache.org/r/20027/