[NFTs] Offchain mint (#13158)

* Allow to mint with the pre-signed signatures

* Another try

* WIP: test encoder

* Fix the deposits

* Refactoring + tests + benchmarks

* Add sp-core/runtime-benchmarks

* Remove sp-core from dev deps

* Enable full_crypto for benchmarks

* Typo

* Fix

* Update frame/nfts/src/mock.rs

Co-authored-by: Squirrel <[email protected]>

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_nfts

* Add docs

* Add attributes into the pre-signed object & track the deposit owner for attributes

* Update docs

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_nfts

* Add the number of attributes provided to weights

* Apply suggestions

* Remove dead code

* Remove Copy

* Fix docs

* Update frame/nfts/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <[email protected]>

* Update frame/nfts/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <[email protected]>

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Co-authored-by: Squirrel <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Oliver Tale-Yazdi <[email protected]>