Create markers from banners

[n-aspen]

I should be able to create markers from banners in a similar way to how they're added to regular maps. The methods needed seem simple enough but I'll have to create the images for the icons myself by getting a list of the patterns in use and then coloring and adding them in order.

For a basic implementation, I think I'll just start with the base color of the banner and work from there. The methods I'll need from a spigot are below.

https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/block/Banner.html
https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/block/banner/PatternType.html
https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/block/banner/Pattern.html