Namespace Pillar Package Table

It seems wrong to me that a formula specific package_table should be in the pillar root level.  This pull request moves it to live with the rest of the pillar data expected by the formula in pillar['salt'].  Additionally, I removed the if/elif statement in favor of pillar.get,  this will provide simple fallback to the hardcoded package_table if the os doesn't exist in the pillar package_table.