bug/include resource tracking and serialization for all pages

[thescientist13]

Related Issue

resolves #1098

Summary of Changes

1. Ended up being a bit of a refactor to make sure all pages had their resources tracked, not just the prerendered one
2. Re-serialize graph.json to include page resources and frontmatter imports and delete graph copy plugin
3. Add specs to cover SSR pages get properly bundled assets

TODO

1. Add test case
2. Try and keep graph.json light weight (maybe try and re-hydrate graph.json from resources.json)
3. track refactoring opportunities into a new or existing issue
4. Handle those 500s as 404s instead (nice to have, otherwise make a ticket) - not found static assets are returning 500 status code when running the serve command #1102