Player System: Basics

**HUD**
- [x] Player health bar
- [x] Player thirsty bar
- [x] Player hungry bar
- [x] Player sleepness bar
- [x] Player strength bar
- [x] On-player money (wallet)
- [x] Player Credits

**Keyboard UIs**
- [x] F3: Main menu
- [ ] ??: Stats window
- [x] Z: Online players window
- [ ] ??: Full reachable players list
- [ ] I: Inventory window