Key Storage Service API

Entity and user device public and private key will be store in Key Storage Service. All this data should be encrypted by other master key that will be stored in HSM.

The reason we don't plan keeping all the key in HSM is because they are limited and we can have quite a lot of key for device and entity.

This API should have method for get and set a key, there should be a mandatory param in both request called type which can be public or private (consider that it will be different size public and private).

So every claim for signing will access that storage.

We should implement Key Storage Service, which will be used mostly from signing service.