Add music to the game

[Turtyo]

Feature Description

Use the audio tracks made by the music inside the game.

Motivation

It will sound way better like that !

Acceptance Criteria

• Each area as its related music (see below for list)
• Music loops inside a given level if it ends too early
• Music changes after a while

Proposed Solution

I would create a global sound reader (I'm not sure of the name inside Godot). The idea behind making it global is that you don't need to recreate it and destroy it between scenes, which simplifies handling transitions.
There is a parameter to automatically loop the music on the music player inside Godot;
We can cut the map in three and play one of the three area music for each section.
So when you move, check the Y coordinate (aka the floor) to see if we are at more than 1/3 and more than 2/3.
So music are for specific areas, like boss music, shop music, heal music...

Implementation Steps (Optional)

Everything can be done at the same time I think.

Additional Context

Here are the musics and the area I think we should use them in:
0 to 33% of the map: Battle area 1.wav
33 to 66% of the map: Battle area 2.wav
66 to 100% of the map: Fauna_floor_3_theme_loop.wav
Boss fight: Boss 1.wav
Shop: Snail_shop_loop.wav
Heal: Sweet_Snail_Healing_loop.wav

Even though shop and heal are either being worked on or not done yet, we can still put the music for those, because we don't need to modify the event. Just need to check the event type when entering a new room (I think there is somewhere that already prints the event type, with a debug var, so we can check that to see how we did it and just copy that)

The boss fight is a normal mob fight, the way to see it's a boss fight is just that it's the last floor of the map (and it's probably the way we will do to decide to spawn a boss, just see that it's the last floor, so it makes sense to do it like that too).