* Created macro to get the metadata form State and Testcase
* Expanded the macros for mutable, or not, State and Testcase metadata
* Created functions on traits HasMetadata and HasNamedMetadatato get, mutable or not, metadata
* Created the functions to get metadata
* Added #[inline] attribute and renamed the functions
* Renamed the functions and added #[inline] attribute
* Temporarily added testcase() function
* Added testcase() function
* Changed Ref import to core::cell:Ref
* Added testcase_mut() and renamed occurences of metadata() and metadata_mut()
* Renamed more occurences
* Renamed the metadata() on impl HasMetadata for NopState
---------
Co-authored-by: Andrea Fioraldi <andreafioraldi@gmail.com>