primitives: Move out of staging released APIs (#3925)

Runtime release 1.2 includes bumping of the ParachainHost APIs up to
v10, so let's move all the released APIs out of vstaging folder, this PR
does not include any logic changes only renaming of the modules and some
moving around.

Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>

cumulus/client/relay-chain-minimal-node/src/blockchain_rpc_client.rs

@@ -26,9 +26,7 @@ use polkadot_core_primitives::{Block, BlockNumber, Hash, Header};
 use polkadot_overseer::{ChainApiBackend, RuntimeApiSubsystemClient};
 use polkadot_primitives::{
 	async_backing::{AsyncBackingParams, BackingState},
-	slashing,
-	vstaging::{ApprovalVotingParams, NodeFeatures},
-	CoreIndex,
+	slashing, ApprovalVotingParams, CoreIndex, NodeFeatures,
 };
 use sc_authority_discovery::{AuthorityDiscovery, Error as AuthorityDiscoveryError};
 use sc_client_api::AuxStore;