Add global domain id offset to conduit wrapper (#3524)

## Summary
Make sure all domains have unique domain ids by adding a global domain
offset

## Additional background
Currently meshes and particles will have non unique domain ids. 

## Checklist

The proposed changes:
- [x] fix a bug or incorrect behavior in AMReX
- [ ] add new capabilities to AMReX
- [ ] changes answers in the test suite to more than roundoff level
- [ ] are likely to significantly affect the results of downstream AMReX
users
- [ ] include documentation in the code and/or rst files, if appropriate

Src/Extern/Conduit/AMReX_Conduit_Blueprint.cpp

@@ -359,6 +359,10 @@ MultiLevelToBlueprint (int n_levels,
     int rank   = ParallelDescriptor::MyProc();
     int ntasks = ParallelDescriptor::NProcs();
 
+    // get global domains already present in node
+    long domain_offset = (long)res.number_of_children();
+    ParallelDescriptor::ReduceLongSum(domain_offset);
+
     Vector<const BoxArray*> box_arrays;
     Vector<int> box_offsets;
 
@@ -398,7 +402,7 @@ MultiLevelToBlueprint (int n_levels,
         for(MFIter mfi(mf); mfi.isValid(); ++mfi)
         {
             // domain_id is mfi.index + all patches on lower levels
-            int domain_id = mfi.index() + num_domains;
+            int domain_id = mfi.index() + num_domains + domain_offset;
             const std::string& patch_name = amrex::Concatenate("domain_",
                                                                domain_id,
                                                                6);

Src/Extern/Conduit/AMReX_Conduit_Blueprint_ParticlesI.H

@@ -215,6 +215,10 @@ ParticleContainerToBlueprint(const ParticleContainer<NStructReal,
     int num_levels = pc.maxLevel() + 1;
     int num_domains = 0;
 
+    // get global domains already present in node
+    long domain_offset = (long)res.number_of_children();
+    ParallelDescriptor::ReduceLongSum(domain_offset);
+
     // loop over levels
 
     int rank   = ParallelDescriptor::MyProc();
@@ -288,7 +292,7 @@ ParticleContainerToBlueprint(const ParticleContainer<NStructReal,
         for (MyParConstIter pti(pc, lev); pti.isValid(); ++pti)
         {
             // this will give us a unique id across levels for each tile
-            int domain_id = lvl_offset + num_lvl_local_tiles;
+            int domain_id = lvl_offset + num_lvl_local_tiles + domain_offset;
 
             const auto& ptile = pti.GetParticleTile();
             const std::string& patch_name = amrex::Concatenate("domain_",