* 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)
* 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