Move transactions protocol to its own crate (#12264)

* Move transaction protocol to its own crate

* Update Cargo.lock

* Fix binaries

* Update client/network/transactions/src/lib.rs

Co-authored-by: Dmitry Markin <[email protected]>

* Update client/service/src/builder.rs

Co-authored-by: Bastian Köcher <[email protected]>

* Apply review comments

* Revert one change and apply cargo-fmt

* Remove Transaction from Message

* Add array-bytes

* trigger CI

* Add comment about codec index

Co-authored-by: Dmitry Markin <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>