Spring Boot Version Up

* Spring Boot 2.5.3 -> Spring Boot 3.0.6

1. JDK 8 -> JDK 17 Version Up

** Maven 라이브러리 중 JDK17 이하를 사용하는 라이브러리 Version Up (없으면 대체 라이브러리 탐색)

1. Java 17
2. Spring Framework 6
3. Jakarta EE 9
4. Gradle 7.5
5. Groovy 4.0
6. Kotlin 1.6
7. Hibernate 6.1

2. Java EE를 jakarta EE 로 대체 (javax.* 에서 jakarta.* 로 변경)

import jakarta.mail.*;  
import jakarta.annotation.PostConstruct;
import jakarta.annotation.Resource;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.persistence.*;
import jakarta.validation.constraints.NotEmpty;
import jakarta.validation.constraints.NotNull;
import jakarta.validation.constraints.NotBlank;
import jakarta.validation.Valid;