Also introduce a "show-peek-icon" property to enable/disable
the peek-password-icon in the password entry. This is useful
in cases where the peeking the password functionality needs
to be avoided.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/619
StPasswordEntry will be put to use for password entries
in various shell dialogs. This is done to have a consistent
behaviour for all password entries and introduce a peek
password functionality for these password entries in the
subsequent commits.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/619