Mark nvcomp zstd compression stable (#12059)

NVCOMP zstd compression was added in 22.10, but marked experimental, meaning you have to define the environment variable `LIBCUDF_NVCOMP_POLICY=ALWAYS` to enable it.  After completing validation testing using the spark rapids plugin as documented here: NVIDIA/spark-rapids#3037, we believe that we can now change the zstd compression status to stable, which will enable it in cudf by default.  `LIBCUDF_NVCOMP_POLICY=STABLE` is the default value.

Authors:
  - Jim Brennan (https://github.com/jbrennan333)

Approvers:
  - Nghia Truong (https://github.com/ttnghia)
  - David Wendt (https://github.com/davidwendt)
  - Vukasin Milovanovic (https://github.com/vuule)

URL: #12059

cpp/src/io/comp/nvcomp_adapter.cpp

@@ -398,7 +398,7 @@ bool is_compression_enabled(compression_type compression)
       return false;
     case compression_type::SNAPPY: return detail::nvcomp_integration::is_stable_enabled();
     case compression_type::ZSTD:
-      return NVCOMP_HAS_ZSTD_COMP and detail::nvcomp_integration::is_all_enabled();
+      return NVCOMP_HAS_ZSTD_COMP and detail::nvcomp_integration::is_stable_enabled();
     default: return false;
   }
   return false;

docs/cudf/source/user_guide/io.md

@@ -170,7 +170,7 @@ If no value is set, behavior will be the same as the "STABLE" option.
     +=======================+========+========+==============+==============+=========+========+==============+==============+========+
     | Snappy                | ❌     | ❌     | Stable       | Stable       | ❌      | ❌     | Stable       | Stable       | ❌     |
     +-----------------------+--------+--------+--------------+--------------+---------+--------+--------------+--------------+--------+
-    | ZSTD                  | ❌     | ❌     | Experimental | Experimental | ❌      | ❌     | Experimental | Experimental | ❌     |
+    | ZSTD                  | ❌     | ❌     | Stable       | Stable       | ❌      | ❌     | Stable       | Stable       | ❌     |
     +-----------------------+--------+--------+--------------+--------------+---------+--------+--------------+--------------+--------+
     | DEFLATE               | ❌     | ❌     | ❌           | ❌           | ❌      | ❌     | Experimental | Experimental | ❌     |
     +-----------------------+--------+--------+--------------+--------------+---------+--------+--------------+--------------+--------+