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/src/light/fetcher.rs

@@ -33,12 +33,10 @@ use state_machine::{
 	read_child_proof_check,
 };
 pub use state_machine::StorageProof;
+use sp_blockchain::{Error as ClientError, Result as ClientResult};
 
 use crate::cht;
 pub use client_api::{
-	error::{
-		Error as ClientError, Result as ClientResult
-	},
 	light::{
 		RemoteCallRequest, RemoteHeaderRequest, RemoteReadRequest, RemoteReadChildRequest,
 		RemoteChangesRequest, ChangesProof, RemoteBodyRequest, Fetcher, FetchChecker,
@@ -329,10 +327,8 @@ pub mod tests {
 	use codec::Decode;
 	use crate::client::tests::prepare_client_with_key_changes;
 	use executor::{NativeExecutor, WasmExecutionMethod};
-	use client_api::{
-		backend::NewBlockState,
-		error::Error as ClientError,
-	};
+	use sp_blockchain::Error as ClientError;
+	use client_api::backend::NewBlockState;
 	use test_client::{
 		self, ClientExt, blockchain::HeaderBackend, AccountKeyring,
 		runtime::{self, Hash, Block, Header, Extrinsic}