Add bulk-delete view and ability to select-and-delete entries from the OnboardingTask list view. (This mostly addresses #26, though I didn't have time today to add a corresponding API endpoint for this operation)
OnboardingTask list view now includes "Add" and "Import" buttons
Views and buttons are now correctly controlled by OnboardingTask user permissions.
Removed unused fields secret, owner, and group_id for now.
secret
,owner
, andgroup_id
for now.