Integrate MSCCL++ DSL to torch workload (#620)

Provides two integration ways for MSCCL++ DSL.
1. Integrate with customized communication group
2. Integrate with NCCL API

Introduce new Python APIs to make it work:
```python
mscclpp.compile # compile dsl to json based execution plan
mscclpp.ExecutionPlanRegistry.register_plan(plan) # register the compiled plan to executionPlanRegistery
mscclpp.ExecutionPlanRegistry.set_selector(selector) # set the selector, the selector will return the best execution plan based on collection, message size, world size....
```
Fix #556

---------

Co-authored-by: Caio Rocha <caiorocha@microsoft.com>
Co-authored-by: Changho Hwang <changhohwang@microsoft.com>

python/csrc/utils_py.cpp

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include <nanobind/nanobind.h>
+#include <nanobind/stl/string.h>
+
+#include <mscclpp/utils.hpp>
+
+namespace nb = nanobind;
+using namespace mscclpp;
+
+void register_utils(nb::module_& m) { m.def("get_host_name", &getHostName, nb::arg("maxlen"), nb::arg("delim")); }