feat(config): add VirtIO block mmio device configuration

[luodeb]

Add VirtioBlkMmioDeviceConfig struct to represent VirtIO block device configuration

[devices]
# Emu_devices.
# Name Base-Ipa Ipa_len Alloc-Irq Emu-Type EmuConfig.
emu_devices = []

# Pass-through devices.
# Name Base-Ipa Base-Pa Length Alloc-Irq.
passthrough_devices = []

[[devices.virtio_blk_mmio]]
# Virtio block device configuration.
# Device ID.
device_id = "vda"
# MMIO base address.
mmio_base = "0x0a000000"
# MMIO size.
mmio_size = "0x200"
# Interrupt type.
interrupt_type = "level"
# Interrupt number.
interrupt_number = 16
# Guest device path.
guest_device_path = "/dev/vda"
# Backend type.
backend_type = "file"
# Backend path.
backend_path = "vm_nimbos.img"
# Image size.
size = "10GB"
# Readonly.
readonly = false
# Serial.
serial = "MMIO_DISK001"

[ZR233]

mmio_size 是代码中定义的吧，是否有必要作为配置项？