Add legacy shim for chatting (TalkPath)

[ksmit799]

The original OTP server intercepted TalkPath_* field updates and handled the filtering/broadcasting of those messages on the CA. The default behaviour of these messages is a broadcast, which makes either filtering impossible or requires modifying the DClass (which isn't feasible for legacy projects.)

The goal of this issue is to add an UberDOG shim that will receive these messages from the CA (if configured to do so) and handle the filtering there. The shim can then send the filtered message back to the CA to be received by clients (following the specific TalkPath field keywords.)

The following is an example of TalkPath dclass's for reference, these are often inherited by player avatars:

struct TalkModification {
  uint16 offset;
  uint16 size;
};

dclass TalkPath_owner {
  setTalk(uint32 fromAV, uint32 fromAC, string avatarName, string chat, TalkModification mods[], uint8 flags) broadcast ownsend;
};

dclass TalkPath_whisper {
  setTalkWhisper(uint32 fromAV, uint32 fromAC, string avatarName, string chat, TalkModification mods[], uint8 flags) ownrecv clsend;
};

dclass TalkPath_group {
  setTalkGroup(uint32 fromAV, uint32 fromAC, string avatarName, string chat, TalkModification mods[], uint8 flags) clsend airecv;
};

dclass TalkPath_account {
  setTalkAccount(uint32 toAc, uint32 fromAC, string fromName, string chat, TalkModification mods[], uint8 flags) airecv clsend;
};

dclass TalkPath_account_group {
  setTalkAccountGroup(uint32, string, string, uint32, TalkModification mods[], uint8 flags) clsend airecv;
};