Rewrite the async code in `BasicQueue` (#7988)

* Rewrite the async code in `BasicQueue`

This is some smaller change to rewrite the async code in `BasicQueue`. I
require this for some other pr I'm working on ;)

* Update primitives/consensus/common/src/import_queue/basic_queue.rs

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

* Update primitives/consensus/common/src/import_queue/basic_queue.rs

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

* Update primitives/consensus/common/src/import_queue/basic_queue.rs

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

* Hmm :D

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