Add project_original table
Add project_original entries on install
Remove unneeded columns and indices from originals

project_id -> project_original.project_id
references -> project_original.references (references are project-specific)
status -> project_original.active
Make list of translations use new table
Use project_original table in status breakdown
Use project_original table in count_by_project_id
Use new table in Original::by_project_id
Remove current branching implementation

Just to clean things up, it served us well.
Fix translations tests to use new table

Factories were unaware that they had to insert a row in another table.