add level dialogs

level dialogs are a little story that tell the user why they need to pass the level.
level dialogs are shown on their own panel (not a popup).

they are a sequence of:

• spoken dialogs (the user does not say anything)
• written dialogs (i.e. someone has sent the user a message)

this means that the dialogs have:

• dialog content (the text)
• the other person