Pool partitioning

[RobDickinson]

Support partitioning a single persistent pool for use by multiple engines at once, and for simultaneous use of a single persistent pool by both pmemkv and pmemobj APIs (from a single process).

[szyrom]

in pmemkv native C/C++ it can be solved by passing PMEMoid/persistent_ptr by config structure, engine can handle this request if it supports multiple engines per pool. But the question remains how to solve it in high level language bindings which are libpmemobj-transparent