fixed some code smells

abstracto-application/abstracto-modules/experience-tracking/experience-tracking-int/src/main/java/dev/sheldan/abstracto/experience/config/features/ExperienceFeatureDisplay.java

@@ -6,8 +6,6 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class ExperienceFeatureDisplay implements FeatureDisplay {
-    public static String EXPERIENCE = "experience";
-
     @Override
     public FeatureEnum getFeature() {
         return ExperienceFeature.EXPERIENCE;

abstracto-application/abstracto-modules/experience-tracking/experience-tracking-int/src/main/java/dev/sheldan/abstracto/experience/models/database/AExperienceLevel.java

@@ -5,6 +5,7 @@ import lombok.*;
 import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.Table;
+import java.io.Serializable;
 
 /**
  * Represents an existing level to reach and the total necessary experience needed to reach that level.
@@ -16,7 +17,7 @@ import javax.persistence.Table;
 @Table(name = "experience_level")
 @Getter
 @Setter
-public class AExperienceLevel {
+public class AExperienceLevel implements Serializable {
     /**
      * The unique level from 0 to as defined in the configuration. Will be created on startup.
      */

abstracto-application/abstracto-modules/experience-tracking/experience-tracking-int/src/main/java/dev/sheldan/abstracto/experience/models/database/AExperienceRole.java

@@ -5,6 +5,7 @@ import dev.sheldan.abstracto.core.models.database.AServer;
 import lombok.*;
 
 import javax.persistence.*;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -19,7 +20,7 @@ import java.util.List;
 @Table(name = "experience_role")
 @Getter
 @Setter
-public class AExperienceRole {
+public class AExperienceRole implements Serializable {
 
     /**
      * The abstracto unique id of this experience role.