feat: add r18 setu api

src/main/kotlin/cn/rtast/fancybot/entity/setu/Setu.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright © 2024 RTAkland
+ * Author: RTAkland
+ * Date: 2024/9/3
+ */
+
+
+package cn.rtast.fancybot.entity.setu
+
+import com.google.gson.annotations.SerializedName
+
+data class Setu(
+    val urls: URLS,
+    val r18: Boolean,
+    @SerializedName("author_id")
+    val authorId: Long,
+) {
+    data class URLS(
+        val large: String
+    )
+}