* Replace deprecated libp2p feature specs with correct ones
* Bump tokio to 1.21.2
* Replace async-std libp2p primitives with tokio ones
* minor: rustfmt
* Fix TestNet to run initialization in the tokio context
* Convert telemetry test from async-std to tokio
* Convert notifications tests from async-std to tokio
* Convert chain sync tests from async-std to tokio
* Ditch async-std completely
* Make executor mandatory
* Bump tokio to 1.22.0
* minor: rustfmt
* Explicitly use tokio runtime in tests
* Move more tests to explicit tokio runtime
* Explicitly set multithreaded runtime in tokio test
* minor: rustfmt
* minor: fix comment
* Replace async-std with tokio in MMR tests