Guide users to using kio-admin instead of sudo

Guide users to using kio-admin instead of sudo

This commit adds a guided setup that leads users from a situation
in which they try to "sudo dolphin" towards them successfully
setting up and using kio-admin.

1. When users enter "sudo dolphin", they are told to start Dolphin
   by typing "dolphin --sudo" or "dolphin --admin" instead.
2. When Dolphin is started with "--sudo" or "--admin" it checks
   whether an "admin" protocol is installed. If not, a guided
   setup leads users towards installing it.
3. After that, Dolphin starts with an installed "admin" protocoll
   like kio-admin. Now a non-modal information dialog appears that
   explains how to activate and use kio-admin.