Create rpgmenu as TopMenu

Other plugins can now add new categories and items to the rpgmenu like
to the sm_admin admin menu.
SMRPG_OnRPGMenuCreated and SMRPG_OnRPGMenuReady can be used to change
the rpgmenu topmenu.
Move command list into seperate plugin

This is some kind of example how to add new stuff to the rpgmenu topmenu
;)