Add host APIs for querying device ctx and remote heap pointer (#200)

* Add host APIs for querying device ctx and remote heap pointer

* Host API to query device pointer for ROCSHMEM_DEFAULT_CONTEXT,
  this is needed to support dynamic module initialization via device kernel
  library bitcode.
* Host API to query remote symmetric heap pointer that can be used in
  custom device kernel for RMA operations.

* Added rocshmem_ptr implementation within the Host Context class
* Enables pointer retrieval functionality for symmetric data objects
* Copy IPC pointers to host memory in RO host context

---------

Co-authored-by: avinashkethineedi <avinash.kethineedi@amd.com>

src/ipc_policy.cpp

@@ -110,7 +110,7 @@ __host__ void IpcOnImpl::ipcHostInit(int my_pe, const HEAP_BASES_T &heap_bases,
   free(vec_ipc_handle);
 
   if (0 == rocshmem_env_.get_ro_disable_ipc()) {
-    int thread_comm_rank;
+    int thread_comm_rank {-1};
 
     CHECK_HIP(hipMalloc(reinterpret_cast<void**>(&pes_with_ipc_avail), shm_size * sizeof(int)));