* Improve UX of HA CLI wrapper and emergency console
For many users, the emergency console gives feeling that the system is
completely broken. However, there are various cases when the system just takes
just a bit longer to start up and the emergency message is shown, while it
finishes a proper startup shortly after. This change tries to improve the UX in
several ways:
* The limit before a forced emergency console startup is changed to 3 minutes
* Waiting can be interrupted with Ctrl+C (reset counter is cleared then)
* Some hints what to check have been added before starting the shell
* Also, because if the HA CLI failed for 5 times in a row in quick succession,
the CLI startup was then not retried anymore and user may have been left with
a black screen, the restart limits timeouts have been adjusted only to back
off and never mark the unit as failed
Closes#4273
* Use /bin/sh and printf to silence linter errors
Since we start the HomeAssistant shell directly on tty the service
responsible for starting did not restart the shell on exit. Remove the
RemainAfterExit flag to make sure that the shell restarts on exit.
* Start ha-cli on tty1 instead of a getty
Instead of starting a getty start the ha-cli directly. This will show
the banner right on startup with the important information such as IP
address of the instance or the URL to reach it.
* Use default shell as root shell instead of HA CLI
Instead of using the ha-cli.sh script as login shell use the regular
shell. Amongst other things, this allows to run VS Code devcontainers
remotely via SSH or using scp. The HA CLI is still available using the
`ha` command.
