Add ConfigHelper to help with extracting values from configs

plugins/civmodcore-paper/src/main/java/vg/civcraft/mc/civmodcore/config/ConfigHelper.java

@@ -0,0 +1,30 @@
+package vg.civcraft.mc.civmodcore.config;
+
+import com.google.common.base.Preconditions;
+import java.util.ArrayList;
+import java.util.List;
+import javax.annotation.Nonnull;
+import org.bukkit.configuration.ConfigurationSection;
+
+public final class ConfigHelper {
+
+	/**
+	 * Retrieves a string list from a given config section. If the keyed value is a standalone string instead of a
+	 * list, that value will be converted to a list.
+	 *
+	 * @param config The config section to retrieve the list from.
+	 * @param key The key to get the list of.
+	 * @return Returns a list of strings, which is never null.
+	 */
+	public static List<String> getStringList(@Nonnull final ConfigurationSection config, @Nonnull final String key) {
+		Preconditions.checkNotNull(config, "Config cannot be null!");
+		Preconditions.checkNotNull(key, "Key cannot be null!");
+		if (config.isString(key)) {
+			final var list = new ArrayList<String>(1);
+			list.add(config.getString(key));
+			return list;
+		}
+		return config.getStringList(key);
+	}
+
+}