[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/Racing.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "CNShardServer.hpp"
+
+struct EPInfo {
+    int zoneX, zoneY, EPID, maxScore, maxTime;
+};
+
+struct EPRace {
+    int ringCount, mode, ticketSlot;
+    time_t startTime;
+};
+
+namespace Racing {
+    extern std::map<int32_t, EPInfo> EPData;
+    extern std::map<CNSocket*, EPRace> EPRaces;
+    extern std::map<int32_t, std::pair<std::vector<int>, std::vector<int>>> EPRewards;
+
+    void init();
+}