Refactor to have ability to categorize projects by next step

Problem/Motivation

As indicated in #3153862: [META] Improve user interface, so it drives what people need to do rather than merely display data we are moving to a UI based on next steps to do. Rather than needing a manual about how the data should be interpreted, we build in best guess interpretations to suggest next steps.

Proposed resolution

1. Expand project collector to add project metadata to projects, including suggested next step.
2. Flatten project structure, merging contributed/custom projects since we now have various other facets that may be more important drivers of the UI.
3. Reflect the removal of special casing of contrib/custom in the paths.
4. Change scanning information storage from json encoded to plain array. Internally it is encoded either way, no need to double encode it. (Makes processing faster)
5. (temporary workaround) Rework upgrade status form to be a massive table of all the data we have. This will not be the primary UI later on and needs to be worked on more.

Remaining tasks

User interface changes

API changes

Data model changes