THRIFT-4653: ES6 classes support (#1615)

* ES6 classes support
* Lint generated code
* ES6 Tests for NodeJS
* Add eslint rules for nodejs
* Run prettier/eslint on nodejs test code
diff --git a/.eslintignore b/.eslintignore
new file mode 100644
index 0000000..dde2dba
--- /dev/null
+++ b/.eslintignore
@@ -0,0 +1,9 @@
+# TODO: Use eslint on js lib and generated code
+
+# Ignore lib/js for now, which uses jshint currently
+lib/js/*
+# Ignore all generated code for now
+**/gen-*
+
+# Don't lint nested node_modules
+**/node_modules