Add basic functionality for ETHELIA.io service

Initial concept of ETHELIA.io (ex PHEIX.io) service was to provide services for data storing on public or private PoA ethereum networks.

For now I suggest to define ETHELIA.io as Ethereum blockchain storage provider for different kinds of events.

The service will based on the next options:

• ✅  Pheix  instance with decentralized authentication enabled;
• ✅  Event endpoint : also Pheix API-only instance with catch contract feature.

To store event we need additional Pheix::Controller::API::Endpoint::Events module: #126 (comment 840185262)