[Refactor] Consolidate MoE quantization parameters into FusedMoeQuantConfig

Consolidates multiple boolean quantization parameters (use_fp8_w8a8, use_int8_w8a8, use_int8_w8a16, use_int4_w4a16, per_channel_quant, block_shape) into a single type-safe FusedMoeQuantConfig object across fused_experts, invoke_fused_moe_kernel, and fused_moe functions.

Key improvements:
- Type-safe configuration with QuantizationType enum
- Factory methods for common quantization patterns
- Built-in validation preventing conflicting configurations
- Seamless backward compatibility with deprecation warnings
- Performance optimizations with cached properties
- Cleaner, more maintainable API for future extensions

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Rahul Tuli <rahul@neuralmagic.com>

Author: rahul-tuli