Feat: es modules (#139)

* All file imports change from commonjs to es-module

* Improved plex error responses back from api

* Converted viewHistory to es module

* Es-module requires file extension, updated all imports

* Fix esmodule not having __dirname defined in scope

* Replace dynamic-require with fs readFileSync

* Short message service module function is exported as default

* Resolved lint issues & ignore import/extension rule until typescript

* All tests file imports changed from commonjs to es-module

* Import json fixtures with new helper

tests/unit/config/testField.js

@@ -1,5 +1,5 @@
-const assert = require("assert");
-const Field = require("../../../src/config/field");
+import assert from "assert";
+import Field from "../../../src/config/field.js";
 
 describe("Field", () => {
   it("should return an array if it is an array", () => {