Add Brightcove module and its dependencies

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

Author: fureigh

composer.json

@@ -7,7 +7,8 @@
         "composer/installers": "^1.0.24",
         "wikimedia/composer-merge-plugin": "^1.4",
         "drush/drush": "^9.1",
-        "drupal/features": "^3.5"
+        "drupal/features": "^3.5",
+        "drupal/brightcove": "^1.3"
     },
     "replace": {
         "drupal/core": "^8.4"
@@ -28,7 +29,8 @@
         ],
         "merge-plugin": {
             "include": [
-                "core/composer.json"
+                "core/composer.json",
+                "modules/brightcove/composer.json"
             ],
             "recurse": false,
             "replace": false,