Some tweaks in the network crate (#1108)

* Move Roles to network::config

* Make network::config public

* Move NetworkConfig and NonReservedMode to config

* Move Params to config

* Move node_id() to NetworkManager and fix tests

* Rename Specialization to NetworkSpecialization

substrate/core/network/src/sync.rs

@@ -25,7 +25,7 @@ use blocks::{self, BlockCollection};
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, As, NumberFor};
 use runtime_primitives::generic::BlockId;
 use message::{self, generic::Message as GenericMessage};
-use service::Roles;
+use config::Roles;
 use import_queue::ImportQueue;
 
 // Maximum blocks to request in a single packet.