Add support for advanced tunnel protocols (L2TP, IKEv2, MASQUE) in `limactl tunnel`

### Description

### **Summary**
The `limactl tunnel` command currently has a TODO comment indicating planned support for advanced tunneling protocols. This feature request proposes implementing L2TP, IKEv2, and MASQUE protocol support to enhance Lima's networking capabilities.

### **Current State**
**File**: `cmd/limactl/tunnel.go` (Line 44)
```go
// TODO: implement l2tp, ikev2, masque, ...
```

Currently, `limactl tunnel` provides basic tunneling functionality, but lacks support for enterprise-grade and modern tunneling protocols.

### **Motivation**
1. **L2TP (Layer 2 Tunneling Protocol)**: Widely used in enterprise VPN solutions, provides better compatibility with corporate networks
2. **IKEv2 (Internet Key Exchange version 2)**: Modern, secure protocol with better performance and mobility support than older VPN protocols
3. **MASQUE (Multiplexed Application Substrate over QUIC Encryption)**: Next-generation protocol offering improved performance and security over HTTPS

### **Proposed Implementation**
1. Extend `limactl tunnel` command with protocol selection flags:
```bash
limactl tunnel --protocol [wireguard|l2tp|ikev2|masque]
```

2. Add protocol-specific configuration options in `lima.yaml`

3. Implement protocol handlers in the tunnel package

4. Add comprehensive documentation for each protocol

### **Benefits**
- Enhanced compatibility with enterprise environments
- Improved security options
- Better performance for specific use cases
- Future-proofing Lima's networking stack

### **Technical Considerations**
- Protocol implementation may require platform-specific code (Darwin, Linux, Windows)
- May need additional dependencies for cryptographic operations
- Should maintain backward compatibility with existing tunnel functionality

### **Environment**
- **Lima Version**: v2.0.1 (latest)
- **Host OS**: Windows 11 / macOS / Linux (cross-platform feature)
- **Related Issue**: This addresses the TODO in `cmd/limactl/tunnel.go:44`

### **Additional Context**
This feature would position Lima as a more robust solution for users requiring advanced networking capabilities, particularly in enterprise and security-conscious environments.