Revamp landing page README

[bpkroth]

trafficstars

• [ ] should include a practical description of what the project enables and how it differs from existing solutions
• [x] ~should include simple instructions on getting started with an example (e.g., sqlite) or starting a new project (template repo)~ #524
• [ ] should include some graphs?
• [x] ~links to separate development environment instructions~ #524
• [ ] roadmap for features?