Implement fedmsg meta methods in fedora messaging schema

[Zlopez]

To have full functionality of fedmsg in fedora messaging, we need to implement fedmsg_meta_fedora_infrastructure methods in the-new-hotness schema.

This will allow any application consuming the-new-hotness messages to have the same functionality as in fedmsg.

[Zlopez]

Implementation details

This issue needs to go through every method in https://github.com/fedora-infra/fedmsg_meta_fedora_infrastructure/blob/develop/fedmsg_meta_fedora_infrastructure/hotness.py and move them to corresponding message class in https://github.com/fedora-infra/the-new-hotness/blob/master/hotness_schema/hotness_schema/messages.py

[Zlopez]

Messaging schema were migrated to separate repository. This issue is now migrated as well. fedora-infra/the-new-hotness-messages#4