Add materials of rarity 4 to items API and sprites for Planner merging

[Blealtan]

To merge Planner into frontend-v2 main site, rarity 4 materials (D32钢 etc.) are required to be added in corresponded API and sprites image. Currently they are omitted since they're not dropped anywhere. We need to decide how to add them into items API and implement it.

[AlvISsReimu]

done