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/network/src/chain.rs

@@ -17,7 +17,7 @@
 //! Blockchain access trait
 
 use client::Client as SubstrateClient;
-use client_api::error::Error;
+use sp_blockchain::Error;
 use client_api::{ChangesProof, StorageProof, ClientInfo, CallExecutor};
 use consensus::{BlockImport, BlockStatus, Error as ConsensusError};
 use sr_primitives::traits::{Block as BlockT, Header as HeaderT};
@@ -162,7 +162,7 @@ impl<B, E, Block, RA> Client<Block> for SubstrateClient<B, E, Block, RA> where
 			return Ok(false);
 		}
 
-		let ancestor = header_metadata::lowest_common_ancestor(self, *block, *base)?;
+		let ancestor = sp_blockchain::lowest_common_ancestor(self, *block, *base)?;
 
 		Ok(ancestor.hash == *base)
 	}