[9715] Implement required basic elements for dual spec learn gossips.
Required DB data for real work. This is final part required at core side for support.
Also note that commit include
* generic implementation money cost gossip menu items so let
implement in DB many money cost gossip operations with _fixed_ cost.
* useful CONDITION_SPELL that let implemtn menu item visible if specific
spell known/don't known also wide used case for diff gossips.
Signed-off-by: VladimirMangos <vladimir@getmangos.com>