Change media modals look in web UI (#15217)

- Change overlay background to match color of viewed image
- Add interactive reply/boost/favourite buttons to footer of modal
- Change ugly "View context" link to button among the action bar

package.json

@@ -83,6 +83,7 @@
     "babel-runtime": "^6.26.0",
     "blurhash": "^1.1.3",
     "classnames": "^2.2.5",
+    "color-blend": "^3.0.0",
     "compression-webpack-plugin": "^6.1.1",
     "cross-env": "^7.0.2",
     "css-loader": "^5.0.1",