more resilient subsystems (#1908)

* backing: extract log target

* bitfield-signing: extract log target

* utils: fix a typo

* provisioner: extract log target

* candidate selection: remove unused error variant

* bitfield-distribution: change the return type of run

* pov-distribution: extract log target

* collator-protocol: simplify runtime request

* collation-generation: do not exit early on error

* collation-generation: do not exit on double init

* collator-protocol: do not exit on errors and rename LOG_TARGET

* collator-protocol: a workaround for ununused imports warning

* Update node/network/bitfield-distribution/src/lib.rs

* collation-generation: elevate warn! to error!

* collator-protocol: fix imports

* post merge fix

* fix compilation

polkadot/node/core/candidate-selection/src/lib.rs

@@ -24,8 +24,10 @@ use futures::{
 	prelude::*,
 };
 use polkadot_node_subsystem::{
-	errors::{ChainApiError, RuntimeApiError},
-	messages::{AllMessages, CandidateBackingMessage, CandidateSelectionMessage, CollatorProtocolMessage},
+	errors::ChainApiError,
+	messages::{
+		AllMessages, CandidateBackingMessage, CandidateSelectionMessage, CollatorProtocolMessage,
+	},
 };
 use polkadot_node_subsystem_util::{
 	self as util, delegated_subsystem, JobTrait, ToJobTrait,
@@ -118,8 +120,6 @@ enum Error {
 	OneshotRecv(#[from] oneshot::Canceled),
 	#[error(transparent)]
 	ChainApi(#[from] ChainApiError),
-	#[error(transparent)]
-	Runtime(#[from] RuntimeApiError),
 }
 
 impl JobTrait for CandidateSelectionJob {