Implement `pallet-assets-freezer` (#3951)
Closes #3342 cc/ @liamaharon TODO: - [x] Improve docs. - [x] Define public interface (See #3342). In case we define public calls to the pallet implementation: - Implement public calls. - Benchmarks. polkadot address: 12gMhxHw8QjEwLQvnqsmMVY1z5gFa54vND74aMUbhhwN6mJR --------- Co-authored-by: command-bot <> Co-authored-by: Liam Aharon <[email protected]>