edit stm32CubeProg.sh to be able to enter stlink serial number

[Bipoeman]

This PR updates the STM32CubeProgrammer flash script to support targeting specific programmers by their serial numbers during SWD operations, and adds support for the J-Link interface.

This PR fixes/implements the following bugs/features

• Feature: Added -n / --serial-number CLI argument parsing.
• Feature: Appended sn=${SERIAL_NUMBER} to the SWD connection string when the argument is provided.
• Feature: Added jlink as a valid interface option (port=JLINK).
• Breaking changes

When multiple ST-Link programmers or evaluation boards are connected to a single host machine, the STM32CubeProgrammer CLI requires a specific serial number to know which device to flash. Without this parameter, the script blindly connects to the first ST-Link it enumerates, which causes flashing failures or accidental overwrites in multi-device test/CI environments.

Additionally, this adds basic routing for the jlink protocol, allowing users using SEGGER J-Link probes to utilize the same script without needing a separate flashing utility.

Validation

• Ensure CI build is passed.
• Demonstrate the code is solid.
• Local Testing: Ran the script on a Linux host with two ST-Link V2 probes connected. Ran ./flash.sh -i swd -f firmware.bin -n <serial_1> and verified only board 1 was flashed.
• Verified getopt handles the new -n flag correctly on both GNU and BSD (macOS) variants.

[fpistm]

Hi @Bipoeman
Thanks for the PR, I'm currently working on the script and will integrate your PR (probably in a different way).
Anyway don't see any stuff related to jlink as it is already supported by the script.

[fpistm]

Superseded by #119