[Feature] Land's inheritance relationship.

## Structure
-  **Main land**
   - sub-land 1
   - sub-land 2
   - sub-land 3

## Description
The focus of function should be between subland and subland. 
**For example:**
 - players trusted by subland should not be trusted by mainland
 - owner of subland may not be trusted by mainland.

## Benefits
This will provide possibilities for the "kingdom" in the server.