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/test/utils/client/src/client_ext.rs

@@ -56,7 +56,7 @@ pub trait ClientExt<Block: BlockT>: Sized {
 		&self,
 		id: BlockId<Block>,
 		justification: Option<Justification>,
-	) -> client::error::Result<()>;
+	) -> sp_blockchain::Result<()>;
 
 	/// Returns hash of the genesis block.
 	fn genesis_hash(&self) -> <Block as BlockT>::Hash;
@@ -152,7 +152,7 @@ impl<B, E, RA, Block> ClientExt<Block> for Client<B, E, Block, RA>
 		&self,
 		id: BlockId<Block>,
 		justification: Option<Justification>,
-	) -> client::error::Result<()> {
+	) -> sp_blockchain::Result<()> {
 		Finalizer::finalize_block(self, id, justification, true)
 	}