Feature #1667: Direct API for nocopy operations on sender-side and receiver-side
Direct API - Add CMA support for netlrts, multicore and pami builds
CMA support for the Direct API is added in the LRTS API implementation (https://charm.cs.illinois.edu/redmine/issues/1803). However, this is limited to just true-rdma layers like gni, pami, ofi, mpi and verbs. The netlrts layer uses a copy based implementation for the Direct API. However, it can still use CMA for intra-host transfers. On the other hand, for multicore and pami (non-lrts layer), the CMA related methods used still need to be functional in order to maintain API consistency.