Add Ostap, moved from Analysis project
Ostap was removed from Analysis (see Analysis!631 (merged)).
This MR adds the removed directories to Bender, since Ostap is only used through Bender. But it may not actually be needed since there is a version of Ostap that is maintained externally. See also discussion in Analysis!628 (merged)
@ibelyaev FIY, please close if this is redundant.
Edited by Marco Cattaneo