Game menu

[Turtyo]

Feature Description

Add a basic game menu that you are brought to when launching the game.

Motivation

Just don't throw your player into the combat directly ! Let's be civilized.

Concept art / Designs

Those are examples, the main things the menu should have for now is:

• Continue
• New game
• Options
• Credits
• Quit

Acceptance Criteria

• The buttons that don't do anything yet should be disabled (continue, options, credits for now)
• New game should load TestingScene.tscn as this the only scene we have for now (this may change)

Proposed Solution

The BG is a texture. Each option is a button. i don't think a texture button should be needed, as we don't instantiate this and we can instead carefully place it.
Buttons have a disabled state so they can be disabled easily.
i'm not sure how quit could quit the game, but I'm sure there is something for that.

Additional Context

We can use a singleton scene switcher. This may be in link with #74 as the scene loader there could also be used as a more global option to load every scene when needed.

[Turtyo]

Note that this was already partially implemented in #86
We already have buttons to go quit, options and "new game" but this needs to be worked with the save system, not totally implemented yet
What is left to do:

• credits
• The actual options scene (we don't really have a lot to change yet)
• Maybe make the buttons accessible by arrow keys ?

The scene switching should be done with the Global Loader

Edit: this could also include styling the buttons so they look better and choosing a font. This last part should probably be done with a mock idea in mind so it can be voted by the team later on