Added support for setting bodyParser limit param via environment variable (#1618)

In the NodeJs environment, the body-parser was set to 1MB, this change makes it configurable with an env variable.

examples/spec-example/nodejs-bodyParser-limit-example/hello/hello.js

@@ -0,0 +1,11 @@
+const process = require("process");
+
+module.exports = async function (context) {
+  let message =
+    "BODY_PARSER_LIMIT received from env variable " +
+    process.env.BODY_PARSER_LIMIT;
+  return {
+    status: 200,
+    body: message,
+  };
+};