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/node/collation-generation/src/lib.rs

@@ -31,7 +31,7 @@ use polkadot_node_subsystem_util::{
 	request_availability_cores, request_persisted_validation_data, request_validation_code,
 	request_validation_code_hash, request_validators,
 };
-use polkadot_primitives::v1::{
+use polkadot_primitives::v2::{
 	collator_signature_payload, CandidateCommitments, CandidateDescriptor, CandidateReceipt,
 	CoreState, Hash, Id as ParaId, OccupiedCoreAssumption, PersistedValidationData,
 	ValidationCodeHash,

polkadot/node/collation-generation/src/tests.rs

@@ -32,7 +32,7 @@ mod handle_new_activations {
 	use polkadot_node_subsystem_test_helpers::{
 		subsystem_test_harness, TestSubsystemContextHandle,
 	};
-	use polkadot_primitives::v1::{
+	use polkadot_primitives::v2::{
 		CollatorPair, Id as ParaId, PersistedValidationData, ScheduledCore, ValidationCode,
 	};
 	use std::pin::Pin;