New base PocketProvider class

src/main/java/com/zixiken/dimdoors/world/PocketProvider.java

@@ -0,0 +1,15 @@
+package com.zixiken.dimdoors.world;
+
+import net.minecraft.world.WorldProvider;
+
+public class PocketProvider extends WorldProvider {
+    @Override
+    public String getDimensionName() {
+        return "Pocket Dimension";
+    }
+
+    @Override
+    public String getInternalNameSuffix() {
+        return "_pocket";
+    }
+}