Scroll tweaks

[Robotgiggle]

Various scroll tweaks, taken from #818

• You can now set the op_id without setting the pattern, which creates a scroll that loads your world's version of the specified pattern when ticked
• There's now a creative mode tab containing all of the scrolls, including ones from addons, using the above feature to load the correct pattern when you grab one and put it in your inventory
• The wandering trader now has a chance to sell one random scroll for 12 emeralds, which only reveals its stroke order when you buy it (finally, a way to get scrolls in skyblock!)
• Config option that controls how likely it is for wandering traders to sell a scroll

[SamsTheNerd]

Few small notes

[SamsTheNerd]

left some small changes. otherwise code looks fine to me. haven't tested it in-game myself though.