feat: footstep sounds

[shnakamura]

Summary

Footsteps are another layer of ambience that will really improve the overall immersion of the game, while also blending within the current mod's content.

Requirements

• [ ] Add dirt footsteps
• [x] Add stone footsteps
• [x] Add wood footsteps
• [x] Add snow footsteps
• [x] Add grass footsteps
• [ ] Add metal footsteps

[shnakamura]

Potential assets for footsteps:

• Snow grass
• Regular grass
• Stone
• Slabs
• Snow
• Wood
• Mud
• Metal