The task logs storage system is refactored to use the `local_storage`
package. Configuration options have also changed:
- `task_logs_path` is renamed to `local_manager_storage_path`, to
emphasise that only the Manager deals with those files, with default
value `./flamenco-manager-storage`.
- `storage_path` is renamed to `shared_storage_path`, to emphasise this
is the storage shared between Manager and Workers, with default value
`./flamenco-shared-storage`.
Task logs are still stored in
`${local_manager_storage_path}/job-{jobUUID[0:4]}/{jobUUID}/task-{taskUUID}.txt`
Manifest task: T99409
