new feature: hil-serial-by-function

[jubeormk1]

While preparing the hil environment, I noticed that it will save time if we can use an alias to link the serials by function, so later on the details of where a target and its usb-uart adapter are connected are hidden from the test scripts.

I have created a set of config files, scripts and services that will handle giving relevant devices a predictable path every time they are added or removed from the hil-host.

This will work like this:

• a new serial device (/dev/tty*) is plug/unplug
• for every /dev/serial/by-id/ device
• look for a "function map" in the serial_map.conf file
• if the device has a defined value in the config file, create the link /dev/serial/by-function/device-value

Having a predictable pattern to address targets and uart adapters make some task trivial. Two examples:

• reset all devices: for device in /dev/serial/by-function/prog_*; do espflash reset -p "$device"; done
• erase all devices flash: for device in /dev/serial/by-function/prog_*; do espflash erase-flash -p "$device"; done

As the maintainer has control of the serial map file, the value can be modified to address details of task for different chip families and new functions can be added to adapt to new requirements.

This PR is aligned with the the task defined in the issue #37

[brainstorm]

@jubeormk1 Curiosity, did you ever come across https://github.com/esp-rs/esp-hal/tree/main/hil-test when setting up our HIL? I just did and thought it might bring good ideas here?