DAOS S3 Mapping
Use libdfs to maintain compatibility with POSIX namespace (lingua franca).
S3 Bucket = DAOS Container
Bucket metadata can be stored in container attributes (https://github.com/daos-stack/daos/blob/master/src/include/daos_cont.h#L436)
S3 Object = DAOS FS File (DFS)
Object metadata can be stored in extended attributes (https://github.com/daos-stack/daos/blob/master/src/include/daos_fs.h)