* Server::overrideDayNightRatio doesn't require to return bool
There is no sense to sending null player, the caller should send a valid object
* Server::init: make private & cleanup
This function is always called before start() and loads some variables which can be loaded in constructor directly.
Make it private and call it directly in start
* Split Server inventory responsibility to a dedicated object
This splits permit to found various historical issues:
* duplicate lookups on player connection
* sending inventory to non related player when a player connects
* non friendly lookups on detached inventories ownership
This reduce the detached inventory complexity and also increased the
lookup performance in a quite interesting way for servers with thousands
of inventories.
