Enable GDA+IPC (#249)

* Enable GDA+IPC
Fix ROCSHMEM_DISABLE_IPC for both RO and GDA

* add more functionality to bootstrap class

we need a few more functions in the boostrap class to be able to fully
handle the rocshmem requirements:
 - add a function to return the list of local ranks
 - provide a groupAllgather operation which takes a vector of ranks
   participating
 - provide a groupAlltoall operation which takes a vector of ranks
   participating

Also, update the functionality of the gda-Alltoall and gda-Allreduce
operations to take advantage of these functions.

* ipc_policy adapted to use bootstrap groupallgather

* bugfix: there was a mistake in computing sendto in groupallgather

* bugfix: shm_size and shm_rank were set in a local variable rather than
the class member

* mpi-bootstrap: remove an unecessary allgather

---------

Co-authored-by: Edgar Gabriel <Edgar.Gabriel@amd.com>

src/rocshmem_gpu.cpp

@@ -51,15 +51,15 @@
 #include "templates.hpp"
 #include "util.hpp"
 
-#if defined(USE_RO)
+#if defined(USE_GDA)
+#include "gda/context_gda_tmpl_device.hpp"
+#elif defined(USE_RO)
 #include "reverse_offload/context_ro_tmpl_device.hpp"
 #elif defined(USE_IPC)
 # if defined(ENABLE_IPC_BITCODE)
 #  include "ipc/backend_ipc.hpp"
 # endif
 #include "ipc/context_ipc_tmpl_device.hpp"
-#elif defined(USE_GDA)
-#include "gda/context_gda_tmpl_device.hpp"
 #else
 #error "Select one backend among USE_RO, USE_IPC, USE_GDA"
 #endif