Remove doubly defined methods from WorkPackage
Don't show done ratio on WorkPackage#show if disabled
Query: remove done_ratio from available columns if disabled
WorkPackage: Don't update parent done_ratio if done_ratio is disabled

The change would appear in the journal and would thus be visible.

Since WorkPackage already knows about the setting, this seems a nicer
solution than preventing the journal from displaying the field.
API v1: Only show issue done_ratio when enabled
Fix translations for issue_done_ratio setting
Hide done ratio in CSV export

Minimal solution: Column still appears, but is empty, no tests.
Use helper method on WorkPackage to check for disabled done_ratio
Merge pull request #423 from opf/feature/hide_issue_progress

Allow disabling done ratio for work packages