Custom world generation/template pool


 * The root tag
 * The namespaced id of the pool
 * minecraft:empty is used in vanilla pools
 * A list of structures to choose from
 * How likely this element is to be chosen when using this pool
 * The properties of this element
 * The namespaced id of the structure to place
 * Can be rigid or terrain_matching
 * Can be minecraft:empty_pool_element to generate no structure, minecaft:list_pool_element when elements is used, and minecraft:legacy_single_pool_element or minecraft:single_pool_element when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The naemspaced id of the processor to use
 * A list of structures to choose from
 * How likely this element is to be chosen when using this pool
 * The namespaced id of the structure to place
 * Can be rigid or terrain_matching
 * Can be minecraft:empty_pool_element to generate no structure, minecaft:list_pool_element when elements is used, and minecraft:legacy_single_pool_element or minecraft:single_pool_element when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The naemspaced id of the processor to use
 * Can be minecraft:empty_pool_element to generate no structure, minecaft:list_pool_element when elements is used, and minecraft:legacy_single_pool_element or minecraft:single_pool_element when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The naemspaced id of the processor to use
 * The naemspaced id of the processor to use