Create ap_sta_config2.sh for new service approach

[akumpf]

This is an EXPERIMENTAL version of the config script for newer boards/distros using a service model instead of cron.

In version 2.x.x:

• it leverages services (i.e. no cron) for monitoring.
• it doesn't hard-code a MAC address (i.e. you can clone the filesystem, and then boot on another pi, though haven't tested that myself yet).
• it's all contained in one script (no secondary cron helper script needed); simpler to debug and tweak.
• it seems to work well on the latest Raspberry Pi OS distro (Bullseye) and can work on the new Pi Zero 2 W.

Created a new file so this can be debugged in parallel without upsetting existing systems that depend on the previous script. May also want to give some explicit info in the README to help new users understand that there are two flavors to choose from.

[akumpf]

Note that this is heavily derived from #3.

I did add back the --no-internet flag (useful as a temporary AP to help get the STA/client wifi onto a network without fully exposing it), though I believe it's one way (if you always use the flag, the IP/routing will be left out, but if you use it once, it'll be added via iptables)... Could probably add a check in the script that removes the routing if was previously added.

edit: and pardon my misspelling on "cron" as "chron" in the script's comments (feel to edit!). I've been spending too much time synching clocks with another tool (chrony) and got my wires crossed. 🤦‍♂️

[ipitio]

I could merge this into my branch to keep things in one place. Looks good!

[MkLHX]

this is really a fucking good idea thank you @akumpf and @ipitio
you can take the lead on ap_sta_config2.sh i you want ;-)
when everything can be test by more users we can build better options like a device/os selector to run the good script (for example)