Create A Dialogue System

## Description
Create a dialogue GUI/API that allows users to have conversations with NPCs.

## Acceptance Criteria
- [x] Players should be able to initiate conversations with NPCs.
- [x] Conversations should be capable of having multiple layers (like a tree with branches).
- [x] NPCs should be able to initiate conversations with players.
- [x] NPC responses should be able to be synced with audio.
- [x] NPCs should have subtitles for their responses.
- [x] Previously chosen topics should be marked as selected.
- [x] A player should be able to select one of several options of what to say.
- [ ] Multiplayer:
- [x] Every player should be able to hear an NPCs response.
- [ ] Only one person should be able to talk to the NPC at once.
- [ ] Every player should be able to see what the other player said to the NPC.
- [ ] There should be a transcript of the conversation up to this point for any player that joins the conversation.

## Implementation Suggestions
- The general theme of the user experience is that of Fallout New Vegas.