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/service/src/error.rs

@@ -16,10 +16,10 @@
 
 //! Errors that can occur during the service operation.
 
-use client;
 use network;
 use keystore;
 use consensus_common;
+use sp_blockchain;
 
 /// Service Result typedef.
 pub type Result<T> = std::result::Result<T, Error>;
@@ -28,7 +28,7 @@ pub type Result<T> = std::result::Result<T, Error>;
 #[derive(Debug, derive_more::Display, derive_more::From)]
 pub enum Error {
 	/// Client error.
-	Client(client::error::Error),
+	Client(sp_blockchain::Error),
 	/// IO error.
 	Io(std::io::Error),
 	/// Consensus error.