Ability to show hidden files

[Sanaki]

The ability to show hidden files would be helpful for some niche uses, but notably is also required (at least on Linux) to be able to load .hack--Link (Japan).iso without an ini edit when named according to Redump's naming scheme. I am unable to verify if dotfiles or the hidden flag are respected on Windows builds, but I assume both are.

Checklist

• Check the latest git build in case it's already implemented.
• Search for other requests of the same feature.