Better JS language integration for Pre-Request scripts and Test scripts (#1422)

* Add tern as dependency

* Add build rule to transpile mjs

* Initial implementation of the auto complete engine

* Separate out the tern server code to separate file

* Added extra type defs for tern server

* Boost the pw completion result to the top of the list

* Added acorn and acorn-walk as dependency

* Semantic linting powered by tern

* Fix DeepCode warnings for js-editor

* Remove unused registerLint tern extension

Co-authored-by: Liyas Thomas <liyascthomas@gmail.com>

helpers/terndoc/pw-pre.json

@@ -0,0 +1,8 @@
+{
+  "!name": "pw-pre",
+  "pw": {
+    "env": {
+      "set": "fn(key: string, value: string)"
+    }
+  }
+}