<effect> element can be used in a kit to apply potion effects directly to a player,
or used to give a custom effect to a potion bottle item.
Duration specifies how long the potion will last, and amplifier determines what level / how strong the potion is.
The effect type is specified by its Minecraft ID.
Effect ID's should be specified without their
|A potion effect||Status Effect ID|
|Duration of the effect.||Time Period||oo (forever)|
|Strength of the effect. The value matches what is displayed to the player in-game, so the first tier of potions have amplifier 1.||Number||1|