[Feature] Add case-insensitive validation for name and aliases fields

[DogmaDragon]

Is your feature request related to a problem? Please describe.
Right now, Stash allows adding identical aliases as the name or other aliases if they have different capitalization. Since search and scraping is already case-insensitive, I feel like this is redundant clutter.

Describe the solution you'd like
Add case-insensitive validation for name and aliases fields in the frontend.

Additional context
This creates weird situations where draft submissions to the stash-box can have the same name added multiple times even though stash-box frontend prevents adding identical aliases.