remove stuff that was moved to providers (bug cleanup)
Merge pull request #1890 from andymckay/cleanup

remove stuff that was moved to providers (bug cleanup)
Make /fireplace/search/featured/ use fireplace-specific serializers for apps in collections (bug 989405)
Merge pull request #1898 from diox/fireplace-collections-serializer

Make /fireplace/search/featured/ use fireplace-specific serializers for apps in collections (bug 989331)
Cachebust icons according to their hash (bug 985290)