- Order of operations was being sorted by idx of individual operations in
BOM table, which made the ordering useless.
- This adds ordering that's sorted from lowest level item to top level
item.
- chore: remove dead functionality. There's no `items` table. Required
item level operations get overwritten on fetching of items /
operations e.g. when clicking on multi-level BOM checkbox.
- test: add test for tree representation
- feat: BOMTree class to get complete representation of a tree