More item schema fixes

items_game changelog:
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* Removed 'disable fancy class select anim' attribute from the following Botkiller weapons (all variants):
- Sniper Rifle
- Medi Gun
- Minigun
- Flame Thrower
- Stickybomb Launcher

Removed to support class select anims now that the class select UI supports jigglebones
The attribute was kept on Scattergun/Rocket Launcher versions due to clipping issues with the affected anims

* Added 'loot rarity' hidden attrib to rarer Botkiller weapons (Blood, Gold Mk. I and Mk. II, Diamond)
- Assigned value of '1' to utilize the loot ui animation reserved for rarer items (not to be confused with Australium/Ultra Rare items, which use value '2')
- These items currently lack this attrib as it was added for Two Cities Update (after their introduction)

* Added 'loot rarity' hidden attrib to MvM-exclusive hats (same change/reasoning as above):
- Robot Running Man
- Tin Pot
- Pyrobotics Pack
- Battery Bandolier
- U-clank-a
- Tin-1000
- Medic Mech-bag
- Bolted Bushman
- Stealth Steeler


* Updated expired event keys to be hidden from Mann Co Catalog:
Summer Key
Naughty Winter Key 2011
Nice Winter Key 2011
Scorched Key
Fall Key 2012
Eerie Key
Naughty Winter Key 2012
Nice Winter Key 2012
Halloween 2013 Key
Nice Winter Key 2013
Naughty Winter Key 2013
Nice Key 2014 Key
Naughty Key 2014 Key
Limited Summer 2014 Key
- This will fix duplicate 'Mann Co Supply Crate Key' entries

* Updated dummy 'Jungle Inferno Collections' entry to have rarities for dummy collections
- Matches rarity scheme used for Tough Break collections