Add tracing support to node (#1940)

* drop in tracing to replace log

* add structured logging to trace messages

* add structured logging to debug messages

* add structured logging to info messages

* add structured logging to warn messages

* add structured logging to error messages

* normalize spacing and Display vs Debug

* add instrumentation to the various 'fn run'

* use explicit tracing module throughout

* fix availability distribution test

* don't double-print errors

* remove further redundancy from logs

* fix test errors

* fix more test errors

* remove unused kv_log_macro

* fix unused variable

* add tracing spans to collation generation

* add tracing spans to av-store

* add tracing spans to backing

* add tracing spans to bitfield-signing

* add tracing spans to candidate-selection

* add tracing spans to candidate-validation

* add tracing spans to chain-api

* add tracing spans to provisioner

* add tracing spans to runtime-api

* add tracing spans to availability-distribution

* add tracing spans to bitfield-distribution

* add tracing spans to network-bridge

* add tracing spans to collator-protocol

* add tracing spans to pov-distribution

* add tracing spans to statement-distribution

* add tracing spans to overseer

* cleanup

polkadot/node/service/src/lib.rs

@@ -28,7 +28,7 @@ use {
 	std::convert::TryInto,
 	std::time::Duration,
 
-	log::info,
+	tracing::info,
 	polkadot_node_core_av_store::Config as AvailabilityConfig,
 	polkadot_node_core_proposer::ProposerFactory,
 	polkadot_overseer::{AllSubsystems, BlockInfo, Overseer, OverseerHandler},
@@ -704,7 +704,10 @@ pub fn new_full<RuntimeApi, Executor>(
 		// given delay.
 		let voting_rule = match grandpa_pause {
 			Some((block, delay)) => {
-				info!("GRANDPA scheduled voting pause set for block #{} with a duration of {} blocks.",
+				info!(
+					block_number = %block,
+					delay = %delay,
+					"GRANDPA scheduled voting pause set for block #{} with a duration of {} blocks.",
 					block,
 					delay,
 				);