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/protocol/sync/extra_requests.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use client_api::error::Error as ClientError;
+use sp_blockchain::Error as ClientError;
 use crate::protocol::sync::{PeerSync, PeerSyncState};
 use fork_tree::ForkTree;
 use libp2p::PeerId;
@@ -283,7 +283,7 @@ impl<'a, B: BlockT> Matcher<'a, B> {
 #[cfg(test)]
 mod tests {
 	use crate::protocol::sync::PeerSync;
-	use client_api::error::Error as ClientError;
+	use sp_blockchain::Error as ClientError;
 	use quickcheck::{Arbitrary, Gen, QuickCheck, StdThreadGen};
 	use rand::Rng;
 	use std::collections::{HashMap, HashSet};