- Accumulate all schemas and their attributes before creating any UI for them.
- Re-ordered schemas according to the design.
- Renamed Xformable to Transforms.
- Made all sections be collapsed by default except the prim type section, Light and Light type
- Removed the "Applied Schemas" section.
- Add a unit test and fix some tests that assumed sections would be
  expanded.
- Make all sections (except materials, which has a special logic) be
  re-orderable in the future.
- Update the documentation to reflect the changes.

Co-authored-by: Sean Donnelly <[email protected]>

…te-Doc.md

Co-authored-by: Sean Donnelly <[email protected]>