IA Phase 2 — Backport IA refresh to server

The scope of this ticket is just within the content of the Develop section within the navigation. So it largely concerns itself with rearranging the nav, and replacing some of the landing pages in the docs-devex repo. It also includes retitling topics to be action-forward.

The Capella devex docs do not include the original FTS pages; just the Search how-to guides. When we port the IA changes back to server the plan is to integrate the new Search how-to guides with the original FTS pages. DOC-11965 integrates the Search how-to guides with the existing FTS pages. We'll have to use a long-lived feature branch to get this change into 7.6.

As for eventing — that will go into the Server develop pages as-is for now.