Implement Hosts API

[FrontEndCoffee]

Documentation: https://dm.realtimeregister.com/docs/api/hosts

Module:

• Add a HostsApi module in the Api namespace
• Add this module to the RealtimeRegister class.

Endpoints:

• Get
• List
• Create
• Update
• Delete

When implementing the endpoints, make sure to include links to the documentation using the @see annotation in docblocks.

Tests:

• Add tests for all the added domain objects
• Add tests for all the added endpoints

[zbrag]

I've created a pullrequest for this feature: #85