Settings: use class constants for properties, create custom writer

- Create Property class for defining config properties
  - Create logic for typed retrival of properties from YAML file
- Add custom save method
  - Retain comments from Comment annotations in the classes
  - Write in a sorted order: first discovered properties are first written to config.yml
- Adjust properties to reflect the current config.yml
- Add sample tests for the retrieval and writing of properties with the new setup

src/main/java/fr/xephi/authme/util/CollectionUtils.java

@@ -3,6 +3,7 @@ package fr.xephi.authme.util;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Utils class for collections.
@@ -58,4 +59,17 @@ public final class CollectionUtils {
     public static <T> boolean isEmpty(Collection<T> coll) {
         return coll == null || coll.isEmpty();
     }
+
+    public static <T> List<T> filterCommonStart(List<T> coll1, List<T> coll2) {
+        List<T> commonStart = new ArrayList<>();
+        int minSize = Math.min(coll1.size(), coll2.size());
+        for (int i = 0; i < minSize; ++i) {
+            if (Objects.equals(coll1.get(i), coll2.get(i))) {
+                commonStart.add(coll1.get(i));
+            } else {
+                break;
+            }
+        }
+        return commonStart;
+    }
 }

src/main/java/fr/xephi/authme/util/StringUtils.java

@@ -117,4 +117,12 @@ public final class StringUtils {
         return "[" + th.getClass().getSimpleName() + "]: " + th.getMessage();
     }
 
+    public static String repeat(String str, int times) {
+        StringBuilder sb = new StringBuilder(str.length() * times);
+        for (int i = 0; i < times; ++i) {
+            sb.append(str);
+        }
+        return sb.toString();
+    }
+
 }