feat(subbanner): 서브 배너 도메인과 링크 불변식을 추가한다

src/main/kotlin/kr/co/vividnext/sodalive/v2/subbanner/domain/SubBanner.kt

@@ -0,0 +1,20 @@
+package kr.co.vividnext.sodalive.v2.subbanner.domain
+
+import java.time.LocalDateTime
+
+data class SubBanner(
+    val id: Long? = null,
+    val placement: SubBannerPlacement,
+    val imagePath: String,
+    val webUrl: String?,
+    val androidDeepLink: String?,
+    val iosDeepLink: String?,
+    val startDate: LocalDateTime?,
+    val endDate: LocalDateTime?
+) {
+    init {
+        require(!webUrl.isNullOrBlank() || !androidDeepLink.isNullOrBlank() || !iosDeepLink.isNullOrBlank()) {
+            "At least one link must be nonblank"
+        }
+    }
+}

src/main/kotlin/kr/co/vividnext/sodalive/v2/subbanner/domain/SubBannerPlacement.kt

@@ -0,0 +1,6 @@
+package kr.co.vividnext.sodalive.v2.subbanner.domain
+
+enum class SubBannerPlacement {
+    HOME_RECOMMENDATION,
+    CONTENT_RECOMMENDATION
+}