Summary:
- Link to "importing a repository" from Config next steps, since it's not
obvious (and the article isn't obviously named).
- Some minor doc tweaks.
- Remove "Roadmap" document since it's super out of date and not very useful.
Test Plan: Regenerated and read documentation.
Reviewers: btrahan, jungejason
Reviewed By: jungejason
CC: aran, jungejason
Maniphest Tasks: T743
Differential Revision: https://secure.phabricator.com/D1384