ADD thumbnail to database (#12)

* ADD thumbnail to database

* ADD thumbnail generation and retrieval functionality

* ADD thumbnail availability check in VideoCard component

* ADD ClipDTO to reduce exposed internals

* REFactor move APIResponse and VideoMetadata to dto package

* REMOVE unused props from VideoCard

* ADD isThumbnailAvailable function

src/main/java/com/ddf/vodsystem/dto/APIResponse.java

@@ -0,0 +1,16 @@
+package com.ddf.vodsystem.dto;
+
+import lombok.Data;
+
+@Data
+public class APIResponse<T> {
+    private String status;
+    private String message;
+    private T data;
+
+    public APIResponse(String status, String message, T data) {
+        this.status = status;
+        this.message = message;
+        this.data = data;
+    }
+}