[슬기로운 멘티생활] Table - 카테고리 (언어)

### Table : languages

- GetMapping("/api/languages")
- language_no : Integer
- language_name : String
- findAllLanguages() 구현
- findAll() 구현

| language_no | language_name |
| -- | -- |
| 1 | Java |
| 2 | JavaScript |
| 3 | Python |
| 4 | C |
| 5 | C++ |
| 6 | C# |
| 7 | Go |
| 8 | Kotlin |