Integrate simple payment handling with WebClient and persist results

src/main/java/_11/asktpk/artisanconnectbackend/dto/OAuthPaymentResponseDTO.java

@@ -0,0 +1,15 @@
+package _11.asktpk.artisanconnectbackend.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class OAuthPaymentResponseDTO {
+    private long issued_at;
+    private String scope;
+    private String token_type;
+    private int expires_in;
+    private String client_id;
+    private String access_token;
+}