[Scenario Editor] Random spell for magic book and spell scroll

[LeHerosInconnu]

I think it would be great to introduce the possibility of setting a random spell in a magic book (even several for the magic book) and in a spell scroll.
There would be:

• random spell of any level
• random combat spell of any level
• random adventure spell of any level
• random spell of level 1 or 2 or 3 or 4 or 5
• random combat spell of level 1 or 2 or 3 or 4 or 5
• random adventure spell of level 1 or 2 or 3 or 4 or 5

With the possibility of adjusting the given spell according to the hero's wisdom level.
All spells are of course determined at the start of the scenario.