Dependency Injection Trait Locker for Uniques Pallet (#11025)

* Create a dependency injection trait named Locker that can be implemented downstream to enable locking of an asset. Use case defined in RMRK substrate pallet PR76

* Formatting

* Change impl Locker function name to is_locked

* Remove unused import

* Add docstring header

* Remove impl_locker file and add Locker trait to frame_support::traits

* Expose Locker from frame_support::traits::misc

* Formatting

* Move to tokens folder

* Move to tokens folder

* Format and remove Locker from misc traits

* Punctuation

* Update frame/support/src/traits/tokens/misc.rs

Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: Giles Cope <[email protected]>