[upload] Ignore specific or all hidden files when uploading directory

[sissbruecker]

Describe your motivation

Since #8032 allows uploading a directory with drag and drop. This adds all files, including hidden files. For example, on macOS you often have a .DS_Store file that the OS adds to directories automatically.

Describe the solution you'd like

We should ignore hiden files, either a set of specific ones such as .DS_Store or all of them. One challenge here is detecting a hidden file - on Mac and Linux those should start with a dot (.), however on Windows files have a specific marker for that which can not be queried through browser APIs.

Describe alternatives you've considered

No response

Additional context

No response