feat(blri): add serial flashing support and refactor CLI structure

[jakezhu9]

In this pull request, I've refactored the command-line interface of the blri tool and added a new flash command. This allows users to directly flash images to the development board via serial port, making the flashing process simpler and more convenient.

Taking bouffalo-hal/bouffalo-rt/examples/blinky-bl808 as an example, from compilation to flashing, you only need to run the following commands:

# Compile
cargo build -p blinky-bl808 --features bl808-dsp --target riscv64imac-unknown-none-elf --release

# Extract the binary image
rust-objcopy --binary-architecture=riscv64 --strip-all -O binary ./target/riscv64imac-unknown-none-elf/release/blinky-bl808 ./target/riscv64imac-unknown-none-elf/release/blinky-bl808.bin

# Fix the image header (CRC and other fields)
cargo blri patch ./target/riscv64imac-unknown-none-elf/release/blinky-bl808.bin

# Flash to the development board
cargo blri flash ./target/riscv64imac-unknown-none-elf/release/blinky-bl808.bin

Screenshot:

[luojia65]

LGTM