Scroll bar on ki messages

[Hazado]

There is no scroll bar in the KI message currently.

Currently any messages that need to scroll also require editing because it is a hack in the python code.

This is problematic because only the person who created the message can edit the message.

[TheScarFr]

What would be required now, is the possibility to scroll the text:

• either with top and bottom arrows (which match the KI current design),
• either with a scroll bar (which doesn't match the KI current design),
• either with the mouse wheel (bad idea for players that have no mouse wheel),
• either with a keyboard key to scroll down and another key to scroll back up.