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

package.json

@@ -6,6 +6,7 @@
     "url": "https://www.opensource.org/licenses/mit-license.php"
   },
   "main": "webserver/server.js",
+  "type": "module",
   "scripts": {
     "start": "SEASONED_CONFIG=configurations/production.json NODE_ENV=production node src/webserver/server.js",
     "dev": "SEASONED_CONFIG=configurations/development.json NODE_ENV=development node src/webserver/server.js",