feat(go): add JSII_NODE to override node entrypoint (#3890)

By default, jsii-go will lookup the node entrypoint from the PATH. This allows users to override with a specific node entrypoint via the JSII_NODE environment variable.

issue: #3889

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By submitting this pull request, I confirm that my contribution is made under the terms of the [Apache 2.0 license].

[Apache 2.0 license]: https://www.apache.org/licenses/LICENSE-2.0

.all-contributorsrc

@@ -1523,6 +1523,15 @@
         "bug"
       ]
     },
+    {
+      "login": "dastbe",
+      "name": "David Bell",
+      "avatar_url": "https://avatars.githubusercontent.com/u/634735?v=4",
+      "profile": "https://github.com/dastbe",
+      "contributions": [
+        "code"
+      ]
+    },
     {
       "login": "Ragnoroct",
       "name": "Will Bender",