various improvements

[EvanBldy]

Problem

• Some requirements are outdated.
• For DepartmentMetadataDescriptorLink / TaskTypeAssetTypeLink tables no primary keys.
• Routes using zou/app/services/tasks_service._convert_rows_to_detailed_tasks are slow due to querying each task.
• When the search index is not configured, it spam many errors in the logs.

Solution

• Upgrade outdated requirements.
• For DepartmentMetadataDescriptorLink / TaskTypeAssetTypeLink tables add index, primary keys, unicity constraint.
• Optimize zou/app/services/tasks_service._convert_rows_to_detailed_tasks to stop querying each task.
• Stop spamming many errors when the search index is not configured.