feat: encodingType 이넘 생성 및 함수형 인터페이스 적용

src/main/java/com/prgrms/shortenurl/service/EncodingType.java

@@ -0,0 +1,22 @@
+package com.prgrms.shortenurl.service;
+
+import com.prgrms.shortenurl.domain.Url;
+
+import java.util.function.Function;
+
+public enum EncodingType {
+    Base62("Base62", UrlService::shortenUrlByBase62),
+    Murmur("MurMur", UrlService::shortenUrlByMurMur);
+
+    private final String name;
+    private final Function<Url, String> encoder;
+
+    EncodingType(String name, Function<Url, String> encoder) {
+        this.name = name;
+        this.encoder = encoder;
+    }
+
+    public String encode(Url url) {
+        return encoder.apply(url);
+    }
+}