Finish migration to v2 primitives (#5037)

* remove v0 primitives from polkadot-primitives

* first pass: remove v0

* fix fallout in erasure-coding

* remove v1 primitives, consolidate to v2

* the great import update

* update runtime_api_impl_v1 to v2 as well

* guide: add `Version` request for runtime API

* add version query to runtime API

* reintroduce OldV1SessionInfo in a limited way

polkadot/runtime/parachains/src/initializer/benchmarking.rs

@@ -17,7 +17,7 @@
 use super::*;
 use frame_benchmarking::benchmarks;
 use frame_system::RawOrigin;
-use primitives::v1::ConsensusLog;
+use primitives::v2::ConsensusLog;
 use sp_runtime::DigestItem;
 
 // Random large number for the digest

polkadot/runtime/parachains/src/initializer/tests.rs

@@ -18,7 +18,7 @@ use super::*;
 use crate::mock::{
 	new_test_ext, Configuration, Dmp, Initializer, MockGenesisConfig, Paras, SessionInfo, System,
 };
-use primitives::v1::{HeadData, Id as ParaId};
+use primitives::v2::{HeadData, Id as ParaId};
 use test_helpers::dummy_validation_code;
 
 use frame_support::{