Token-swap-over-bridge pallet (#944)

* token swap pallet

* token swap type (replay protection)

* post-merge fixes

* post-merge fix

* Update modules/token-swap/src/lib.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Update modules/token-swap/src/lib.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* add missing comment part

* Update modules/token-swap/src/lib.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* starting claim after lock period is over is forbidden

* move spec_version and weight to arguments

Co-authored-by: Tomasz Drwięga <[email protected]>