Update README.md and other docs, Add devnotes.md

[Capital-Asterisk]

The universe stuff in progress is taking quite a bit.

• Update README
  • Update information to the current state of the codebase.
  • Revise first paragraph
  • Removed misleading list of ideas from Features section; replaced with current features we actually have implemented.
  • Add "Resources" section
• Update dependency graph and explanation in architecture.md
• Remove outdated testapp readme
• Add devnotes.md. I feel like this is useful for quick notes and non-final documentation for whoever is working on the codebase. Likely a little more straightforward compared to needing to dig through github issues.