Disable file viewer through a --no-view-file flag

[tomzx]

Is your feature request related to a problem? Please describe.
We use gdu to give access to users to look at their disk usage on a shared file system.
This is done through a web UI using something like GoTTY.

We would like to be able to pass something like --no-view-file (similar to --no-delete) which would disable the ability to use gdu to view files.

Describe the solution you'd like
A new flag --no-view-file which prevents user from viewing files (using the v shortcut)

Describe alternatives you've considered
n/a

Additional context
n/a