Fixes some issues in trader configs left in Lost Alpha. (New game is NOT required!)
- Added missing items to generic trading sections so that you sell items to random NPCs at normal prices and not overly high (BM-16 long, new food and new monster parts are affected by this oversight)
- Fixed condition for Sidorovich that prevented him from extending his supplies after Agroprom mission
PS: I might continue to expand these fixes as I progress through the game. I see many small issues here in there like trader selling lots of AP ammo but not enough FMJ ammo, missing items etc. Also I don't like how trader sections have a lot of duplicated code and don't use LTX section inheritance.