Add new model for "rescue" process

[lonamiaec]

We're reading the origin_host from topics, so every system owner of a topic must specify the origin host, creating many duplicated values.
It would be easier to have a specific model to keep origin_host values, and if the recovery process is enabled or not.
The proposed schema would be

• id
• origin_host
• enabled

Once this model is in place, we would need to update the get_recovery_hosts() method from the Messaging module to read from the new model instead of the topic's data.