Feat: add translations to default build source paths (elastic/kibana-plugin-helpers#48)

* feat: add translations path to build

included by default, to better match what's in the elastic products and even the plugin template

also add a translations path to the mock plugin for tests

* chore: add script to run tests with linting

Original commit: elastic/kibana-plugin-helpers@9871a4b11d

packages/kbn-plugin-helpers/lib/plugin_config.js

@@ -11,7 +11,7 @@ module.exports = function (root) {
   const buildSourcePatterns = [
     'package.json',
     'index.js',
-    '{lib,public,server,webpackShims}/**/*',
+    '{lib,public,server,webpackShims,translations}/**/*',
   ];
 
   // add shrinkwrap and lock files, if they exist

packages/kbn-plugin-helpers/package.json

@@ -14,6 +14,7 @@
   "license": "Apache-2.0",
   "scripts": {
     "test": "npm run lint && npm run jest",
+    "test:only": "npm run jest",
     "jest": "jest",
     "lint": "eslint bin/ help/ tasks/"
   },

packages/kbn-plugin-helpers/tasks/build/__fixtures__/test_plugin/translations/es.json

@@ -0,0 +1,4 @@
+{
+  "UI-WELCOME_MESSAGE": "Cargando Kibana",
+  "UI-WELCOME_ERROR": "Kibana no se cargó correctamente. Heck la salida del servidor para obtener más información."
+}