[DialoguePage Refactor Step 2] Nametag refactor

[PringlesGang]

Refactors the whole nametag system for more extensibility, maintainability, and readability

Makes use of an abstract base class approach for the NametagDisplay
Similarly overhauls the DialogueBox class to make better use of the new nametag system

Adds ownership from DialoguePage -> DialogueBox -> NametagDisplay, as each DialoguePage in the MAGES. engine maintains its own textbox state
(I am aware this ownership unnecessarily allocated DialogueBoxes for every backlog and tip entry. I pinky-promise I will finally separate these two from DialoguePage next refactor!)

I also cleaned up the DialoguePage class a bit with how it interacts with the names
Game-specific hud element implementations have also been moved from src/games/game-name to src/hud/game-name

src/hud/nametagdisplay and src/hud/dialoguebox have been completely rewritten, so I suggest reviewing those as effectively "new files," instead of looking at the git diff

Definitely also let me know if you disagree with this overall design, or if you have some better ways (part of) this could be structured

[KKhanhH]

I like the new api design a lot more, definitely a lot cleaner