Warp sync part I (#9227)

* Started warp sync

* BABE & GRANDPA recovery

* Warp sync protocol

* Sync warp proofs first

* Added basic documentation

* Apply suggestions from code review

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Style changes

* Apply suggestions from code review

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* fmt

* Apply suggestions from code review

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Fixed chage trie pruning wrt missing blocks

* Restore parent finalization

* fmt

* fmt

* Revert pwasm-utils bump

* Change error type & check API version

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Build fix

* Fixed target block check

* Formatting

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/primitives/finality-grandpa/src/lib.rs

@@ -492,7 +492,7 @@ sp_api::decl_runtime_apis! {
 	/// applied in the runtime after those N blocks have passed.
 	///
 	/// The consensus protocol will coordinate the handoff externally.
-	#[api_version(2)]
+	#[api_version(3)]
 	pub trait GrandpaApi {
 		/// Get the current GRANDPA authorities and weights. This should not change except
 		/// for when changes are scheduled and the corresponding delay has passed.
@@ -530,5 +530,8 @@ sp_api::decl_runtime_apis! {
 			set_id: SetId,
 			authority_id: AuthorityId,
 		) -> Option<OpaqueKeyOwnershipProof>;
+
+		/// Get current GRANDPA authority set id.
+		fn current_set_id() -> SetId;
 	}
 }