Make BlockImport and Verifier async (#8472)

* Make grandpa work

* Introduce `SharedData`

* Add test and fix bugs

* Switch to `SharedData`

* Make grandpa tests working

* More Babe work

* Make it async

* Fix fix

* Use `async_trait` in sc-consensus-slots

This makes the code a little bit easier to read and also expresses that
there can always only be one call at a time to `on_slot`.

* Make grandpa tests compile

* More Babe tests work

* Fix network test

* Start fixing service test

* Finish service-test

* Fix sc-consensus-aura

* Fix fix fix

* More fixes

* Make everything compile *yeah*

* Fix build when we have Rust 1.51

* Update client/consensus/common/src/shared_data.rs

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

* Update client/consensus/common/src/shared_data.rs

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

* Update client/consensus/common/src/shared_data.rs

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

* Update client/consensus/common/src/shared_data.rs

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

* Update client/consensus/common/src/shared_data.rs

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

* Update client/consensus/babe/src/tests.rs

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

* Update client/consensus/babe/src/tests.rs

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

* Fix warning

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

substrate/bin/node-template/pallets/template/src/benchmarking.rs

@@ -5,7 +5,7 @@ use super::*;
 use frame_system::RawOrigin;
 use frame_benchmarking::{benchmarks, whitelisted_caller, impl_benchmark_test_suite};
 #[allow(unused)]
-use crate::Module as Template;
+use crate::Pallet as Template;
 
 benchmarks! {
 	do_something {