Add the Entity Embed and Embed modules

This is a precursor to making it possible to embed Brightcove
videos via the WYSIWYG.

https://github.com/18F/nsf/issues/78

Author: fureigh

composer.json

@@ -10,7 +10,9 @@
         "drupal/features": "^3.5",
         "drupal/brightcove": "^1.3",
         "drupal/inline_entity_form": "^1.0@beta",
-        "drupal/time_formatter": "1.x-dev"
+        "drupal/time_formatter": "1.x-dev",
+        "drupal/entity_embed": "^1.0",
+        "drupal/embed": "^1.0"
     },
     "replace": {
         "drupal/core": "^8.4"