[Request] Add configurable interval for startMessages

[Zytheus]

Just as the normal messages=[] field has the timeBetweenMessages=, I'd like the startMessages=[] field to also have an equivalent. I would also like the start messages to have the ability to perform the same denyMovement action as the end of quest messages.

The idea is to have some sort of starting dialogue that flows more like an NPC talking to a player vs a wall of text just appearing on click.