RFC 0026: Host chain discovery and name resolution

[valentinfernandez1]

Closes #352.

[pgherveou]

I would add a single method that takes all the identifiant we want to resolve. It should be enough.

Also as you are adding this you can fix all the hard coded genesis hash from the other comment api tests

[johnthecat]

I think more ergonomic and focused API would be

enum ChainIdentifier {
  relay,
  people,
  /// ...
}

struct ChainInfo {
  genesisHash: [u8; 32],
  name: String,
  /// ...
}

fn getChainInfo(ChainIdentifier): ChainInfo;

User don't need a full mapping every time where later he need to pick specific chain from list

[valentinfernandez1]

Thanks for the feedback, it's been implemented so feel free to review again