Infrastructure improvements (#2897)

* Factor out runtime module into utils.

* Add maybe_authority information to `PeerConnected` event.

We already gather this information in authority discovery, so we might
as well share it with others.

This opens up an easy path to trigger validators differently from normal
nodes, e.g. for prioritization. This change has become more important
now, that we just connect to all validators and therefore just have a
long peer list without any information about those nodes.

* Test fix.

polkadot/node/network/protocol/src/request_response/mod.rs

@@ -154,7 +154,7 @@ impl Protocol {
 				name: p_name,
 				max_request_size: 1_000,
 				// Available data size is dominated code size.
-                // + 1000 to account for protocol overhead (should be way less).
+				// + 1000 to account for protocol overhead (should be way less).
 				max_response_size: MAX_CODE_SIZE as u64 + 1000,
 				// We need statement fetching to be fast and will try our best at the responding
 				// side to answer requests within that timeout, assuming a bandwidth of 500Mbit/s
@@ -199,7 +199,7 @@ impl Protocol {
 				// waisting precious time.
 				let available_bandwidth = 7 * MIN_BANDWIDTH_BYTES / 10;
 				let size = u64::saturating_sub(
-                    STATEMENTS_TIMEOUT.as_millis() as u64 * available_bandwidth / (1000 * MAX_CODE_SIZE as u64),
+					STATEMENTS_TIMEOUT.as_millis() as u64 * available_bandwidth / (1000 * MAX_CODE_SIZE as u64),
 					MAX_PARALLEL_STATEMENT_REQUESTS as u64
 				);
 				debug_assert!(