Remove all (non-dev) client references from frame, activate dependency enforcer (#4184)

* Move transaction pool to primitives

* move backend, errors into primitives

* remove unused client depencies

* Move rpc-api into primitives

* Move peerset back to client

* Move rpc/api back to client, move palette/support/rpc into utils

* move support-rpc into subfolder

* move system-rpc into utils

* move transaction-pool  and -graph back into client

* fix broken imports

* Clean up test primitives

* Make support test utils independent of frame

* remove unnecessary node dependencies from service

* Reactivate dependency script:
 - only enforce the now achieved status quo will remain
 - allow for primitives to depend on /client for now without failing
 - more discriptive error message so people understand, what it wants
 - minor fix to differentiative between ../client and /client (which may be a subfolder)
 - don't allow this to fail anylonger.

* fix doc comment

* 'Should not' rather than 'must not'.

* Revert unwanted dependency changes

* fix faulty import

* fixup derive_more version

* fix wrong import path

substrate/client/rpc/src/author/mod.rs

@@ -24,7 +24,7 @@ use futures::future::{FutureExt, TryFutureExt};
 use log::warn;
 
 use client::Client;
-use client_api::error::Error as ClientError;
+use sp_blockchain::Error as ClientError;
 
 use rpc::futures::{
 	Sink, Future,

substrate/client/rpc/src/chain/mod.rs

@@ -288,6 +288,6 @@ fn subscribe_headers<B, E, Block, RA, F, G, S, ERR>(
 	});
 }
 
-fn client_err(err: client::error::Error) -> Error {
+fn client_err(err: sp_blockchain::Error) -> Error {
 	Error::Client(Box::new(err))
 }

substrate/client/rpc/src/state/mod.rs

@@ -184,7 +184,7 @@ pub fn new_full<B, E, Block: BlockT, RA>(
 		RA: Send + Sync + 'static,
 		Client<B, E, Block, RA>: ProvideRuntimeApi,
 		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api:
-			Metadata<Block, Error = client::error::Error>,
+			Metadata<Block, Error = sp_blockchain::Error>,
 {
 	State {
 		backend: Box::new(self::state_full::FullState::new(client, subscriptions)),
@@ -332,6 +332,6 @@ impl<B, E, Block, RA> StateApi<Block::Hash> for State<B, E, Block, RA>
 	}
 }
 
-fn client_err(err: client::error::Error) -> Error {
+fn client_err(err: sp_blockchain::Error) -> Error {
 	Error::Client(Box::new(err))
 }

substrate/client/rpc/src/state/state_full.rs

@@ -28,7 +28,8 @@ use rpc::{
 };
 
 use api::Subscriptions;
-use client_api::{backend::Backend, error::Result as ClientResult};
+use client_api::backend::Backend;
+use sp_blockchain::Result as ClientResult;
 use client::{
 	Client, CallExecutor, BlockchainEvents, 
 };
@@ -232,7 +233,7 @@ impl<B, E, Block, RA> StateBackend<B, E, Block, RA> for FullState<B, E, Block, R
 		RA: Send + Sync + 'static,
 		Client<B, E, Block, RA>: ProvideRuntimeApi,
 		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api:
-			Metadata<Block, Error = client::error::Error>,
+			Metadata<Block, Error = sp_blockchain::Error>,
 {
 	fn call(
 		&self,

substrate/client/rpc/src/state/state_light.rs

@@ -40,9 +40,9 @@ use rpc::{
 
 use api::Subscriptions;
 use client_api::backend::Backend;
+use sp_blockchain::Error as ClientError;
 use client::{
-	BlockchainEvents, Client, CallExecutor, 
-	error::Error as ClientError,
+	BlockchainEvents, Client, CallExecutor,
 	light::{
 		blockchain::{future_header, RemoteBlockchain},
 		fetcher::{Fetcher, RemoteCallRequest, RemoteReadRequest, RemoteReadChildRequest},