Creates a salvage area for recovering stranded boards, topics and posts.

• Creates a "Salvage Area" category and a "Salvaged Messages" board
• If any topics are found that don't have an existing board, they are moved to a "Salvaged Board" within this category
• "Salvaged Messages" board contains any messages that didn't have existing topics
• This category also contains any boards that didn't have an existing category or parent
• ID of Salvage Area category stored in $salvageCatID global variable
• ID of Salvaged Messages board stored in $salvageBoardID global variable