Add ability to move free challenges from start of the list to end of it.

src/main/java/world/bentobox/challenges/Settings.java

@@ -37,6 +37,10 @@ public class Settings implements DataObject
 	@ConfigComment("Add enchanted glow to completed challenges")
 	private boolean addCompletedGlow = true;
 
+	@ConfigComment("")
+	@ConfigComment("This indicate if free challenges must be at the start (true) or at the end (false) of list.")
+	private boolean freeChallengesFirst = true;
+
 	@ConfigComment("")
 	@ConfigComment("This list stores GameModes in which Challenges addon should not work.")
 	@ConfigComment("To disable addon it is necessary to write its name in new line that starts with -. Example:")
@@ -109,6 +113,15 @@ public Set<String> getDisabledGameModes()
 	}
 
 
+	/**
+	 * @return freeChallengesFirst value.
+	 */
+	public boolean isFreeChallengesFirst()
+	{
+		return this.freeChallengesFirst;
+	}
+
+
 	@Override
 	public void setUniqueId(String uniqueId)
 	{
@@ -159,4 +172,13 @@ public void setDisabledGameModes(Set<String> disabledGameModes)
 	{
 		this.disabledGameModes = disabledGameModes;
 	}
+
+
+	/**
+	 * @param freeChallengesFirst new freeChallengesFirst value.
+	 */
+	public void setFreeChallengesFirst(boolean freeChallengesFirst)
+	{
+		this.freeChallengesFirst = freeChallengesFirst;
+	}
 }