[IDEA] Put a list of available snapshots in /boot

[mk01]

@adepssimius

CurlyMo has initramfs extended with wifi support, but for official stable it has been dropped.

The telnet has no other dependencies and is processed at two stages. Imagine boot as two steps. One is initramfs. Normally it takes 2-3s if there is nothing to do. Then root is mounted and init started. There begins 2nd stage.

If you have telnet as parameter this happens:
1) if initramfs phase is interrupted, telnetd server is created. Nothing less nothing more. So reason for which initramfs was interrupted is not condition for telnetd, neither if you started network from kernel. It is only up to you if you allows network at kernel stage (ip=dhcp) and/or if you decide, that initramfs stage will hold for you unconditionally (rescue). This is the only way to do VERY LOW LEVEL maintenance if you don't have physical access. Without rescue even with telnet and with ip=dhcp initramfs will not wait for you and until no error happened 2nd stage is started instantly.
2) telnet has its use even after initramfs phase. Imagine network config went wrong. Or /etc/ completely. Or there is service in S runlevel which won't stop so runlevel 2 won't be started and this would mean no net, no multiuser mode not even CONSOLE at physical access. Telnet there means that as /sbin/init is started from initramfs, telnetd is immediately after predeceasing all other possibilities for system to fail. But you can login and fix - again makes sense only if net is configured somewhere (ip=dhcp)

the first telnet session is stopped as initramfs passes - so normally is not even started within the 2-3s. the second telnetd is stopped automatically as soon as net is configured - so most part of startup is ok and ssh is available -- so telnet can be sure you are not left without access.

All this was implemented because I'm a bit lazy. And walking to RPI, handling SD card in another PC etc. It is too much demanding. that way I don't have to move from place until BOOT gets completely corrupted.