[Migrated] Remove unneeded Storage Class attributes

Issue automatically imported from old repo: https://github.com/EmbarkStudios/rust-gpu/issues/568
Old labels: t: enhancement,t: good first issue
Originally creatd by XAMPPRocky on 2021-03-31T11:43:53Z

With recent changes to how we specify the storage class of a variable, we've managed to eliminate the need for a few of the storage class attributes in cases where we can successfully infer all possible valid uses. Mainly the input, output, private, function, generic, and uniform_constant attributes at the time of this writing are no longer needed and should be removed now that they can't be used for anything useful.

Non vengono indicati file sorgente o test. Inizia individuando la gestione dell'attributo storage-class per input, output, private, function, generic e uniform_constant, quindi esamina in che modo le modifiche recenti all'inferenza influiscano sui relativi usi validi. Il lavoro è completo quando vengono rimossi gli attributi che non possono più avere uno scopo utile e vengono aggiornati i controlli o i test pertinenti.