Cleanup page structure

[just-be-dev]

Our pages directory could use some cleanup. I'd experimented with adding remix style structure in #726, but I'm honestly not sure that structure is a good fit.

I'm roughly thinking about this structure:

layouts/
├─ root.tsx
├─ orgs.tsx
└─ projects.tsx
pages/
├─ login.tsx
├─ orgs/
│  ├─ projects/
│  │  ├─ access.tsx
│  │  ├─ disks.tsx
│  │  ├─ disks.[name].tsx
│  │  ├─ instances.tsx
│  │  └─ instances.[name].tsx
│  └─ projects.[name].tsx
└─ orgs.[name].tsx

[david-crespo]

We can just do this if we feel like it, we don't need to consider it a task to keep track of.