Implement flashlight

[snipercup]

Requires #498
Idk if this is a good first issue, but once we have nighttime, we will also need flashlight functionality. For this issue, I will keep it simple:

• Add another light to level_generation.tscn below the FrontLight. This light will be off by default and when it shines, the light will be more narrow then FrontLight.
• When the player equips the flashlight item in the equippedleft or equippedright slot, the light turns on.

Optionally (bonus)

• Have functionality to turn the flashlight on and off. We can toggle it using the left mouse button when it's equipped. We will need some kind of label or tooltip to show it's state.