Ask for password when impersonating

[beccon4]

Impersonating an user gives you access to all of his/her data and communications which is quite a strong security issue. When an admin account issues i.e. an app upgrade etc. Nextcloud asks for the admin password though nothing bad would happen.

Suggestion: Ask for that password before impersonating someone (and file a report into the log)

[eibex]

I keep installing, impersonating and uninstalling the app because of this.
Would be a great enhancement.