Revert "add option restart online player limit"

This reverts commit 879723e0c4bfed0af44abf70391d2558e3a6437e.
Revert "Revert "add option restart online player limit""

This reverts commit 0ba7a3dbee1cf0737a9c582e6d3c15f674762fec.
refactor and merge unload chunk in to save world