Make transaction pool prune transactions only of canonical blocks (#6123)

* Make tx pool aware of retracted fork blocks

* Make it compile

* Update client/transaction-pool/src/lib.rs

Co-authored-by: Nikolay Volf <nikvolf@gmail.com>

* Fix doc test

* Simplify the implementation

* Send tree route as arc to prevent heavy clones

* Switch to use `ExtrinsicHash` to make it more clear

* Fix benchmark

Co-authored-by: Nikolay Volf <nikvolf@gmail.com>