[refactor] Remove the word 'Manager' from most source files/namespaces

ChatManager -> Chat
MissionManager -> Missions
NanoManager -> Nanos
TransportManager -> Transport
ChunkManager -> Chunking
BuddyManager -> Buddies
GroupManager -> Groups
RacingManager -> Racing
ItemManager -> Items

NPCManager and PlayerManager remain.

Note: You can use git log --follow src/file.cpp to trace the history of
a file from before it was renamed.

src/Items.hpp

@@ -0,0 +1,72 @@
+#pragma once
+
+#include "CNShardServer.hpp"
+#include "Player.hpp"
+#include "MobAI.hpp"
+
+struct CrocPotEntry {
+    int multStats, multLooks;
+    float base, rd0, rd1, rd2, rd3;
+};
+
+struct Crate {
+    int rarityRatioId;
+    std::vector<int> itemSets;
+};
+
+struct MobDropChance {
+    int dropChance;
+    std::vector<int> cratesRatio;
+};
+
+struct MobDrop {
+    std::vector<int> crateIDs;
+    int dropChanceType;
+    int taros;
+    int fm;
+    int boosts;
+};
+
+namespace Items {
+    enum class SlotType {
+        EQUIP = 0,
+        INVENTORY = 1,
+        BANK = 3
+    };
+    struct Item {
+        bool tradeable, sellable;
+        int buyPrice, sellPrice;
+        int stackSize, level, rarity;
+        int pointDamage, groupDamage, fireRate, defense, gender;
+        int weaponType;
+        // TODO: implement more as needed
+    };
+    // hopefully this is fine since it's never modified after load
+    extern std::map<std::pair<int32_t, int32_t>, Item> ItemData; // <id, type> -> data
+    extern std::map<int32_t, CrocPotEntry> CrocPotTable; // level gap -> entry
+    extern std::map<int32_t, std::vector<int>> RarityRatios;
+    extern std::map<int32_t, Crate> Crates;
+    // pair <Itemset, Rarity> -> vector of pointers (map iterators) to records in ItemData (it looks a lot scarier than it is)
+    extern std::map<std::pair<int32_t, int32_t>,
+        std::vector<std::map<std::pair<int32_t, int32_t>, Item>::iterator>> CrateItems;
+    extern std::map<std::string, std::vector<std::pair<int32_t, int32_t>>> CodeItems; // code -> vector of <id, type>
+
+    // mob drops
+    extern std::map<int32_t, MobDropChance> MobDropChances;
+    extern std::map<int32_t, MobDrop> MobDrops;
+
+    void init();
+
+    // mob drops
+    void giveMobDrop(CNSocket *sock, Mob *mob, int rolledBoosts, int rolledPotions, int rolledCrate, int rolledCrateType, int rolledEvent);
+
+    int findFreeSlot(Player *plr);
+    Item* getItemData(int32_t id, int32_t type);
+    void checkItemExpire(CNSocket* sock, Player* player);
+    void setItemStats(Player* plr);
+    void updateEquips(CNSocket* sock, Player* plr);
+
+#ifdef ACADEMY
+    extern std::map<int32_t, int32_t> NanoCapsules; // crate id -> nano id
+#endif
+}