feat: created RoleEnum according to standard

src/main/java/uulm/teamname/marvelous/gamelibrary/json/basic/RoleEnum.java

@@ -0,0 +1,8 @@
+package uulm.teamname.marvelous.gamelibrary.json.basic;
+
+/** Enum containing the basic roles as defined by the network standard */
+public enum RoleEnum {
+    PLAYER,
+    KI,
+    SPECTATOR,
+}