* Update roc_shmem_ctx_fence API to use team-relative PE numbering
* Update backend to populate team_opaque member of ROC_SHMEM_CTX_DEFAULT (used to store information about the team wrt TEAM_WORLD)
code is based on the GPUIB implementations of the routines, which seem
however generic enough to work also for the IPC conduit.
Some code is in for broadcast, fcollect, and alltoall.
* add backend_ipc.{cpp & hpp}
* rename context_ipc.{cpp & hpp} to context_ipc_device.{cpp & hpp}
* add host interface to IPC backend
* add context_ipc_host.{cpp & hpp} to support host interface
* add USE_RO compile flag to enable support for single backend interface at a time
* add ipc_single script to build rocSHMEM with IPC backend
avinashkethineedi
Edgar Gabriel