Add files property to package.json to only package dist folder

.npmignore

@@ -1,5 +0,0 @@
-node_modules
-coverage
-typings
-test
-tmp

package.json

@@ -12,6 +12,9 @@
     "type": "git",
     "url": "https://github.com/Microsoft/powerbi-router"
   },
+  "files": [
+    "dist"
+  ],
   "keywords": [
     "microsoft",
     "powerbi",