The "Overview" link previously went to a summary of Consul features and a
comparison to other products. This commit restores that destination at the
request of Consul PMs.
This commit previously removed the link (it went to `/` instead of `/intro`).
ac612a9cdc (diff-f98b55875118725d1373dd2da36d9ee5)
This removes "Intro", which is actually no longer the recommended
get-started place (Learn takes that spot).
Additionally, there is now a separator between the high level business
value stuff, and the low level developer stuff.
Geoffrey Grosenbach