Create a (shell/bash?) start script for the bot

[Amunak]

The bot needs a start script that:

• runs the bot in a loop in case it crashes so that it can get back up
• listens for the bot's exit code and can detect:
  • proper shutdowns (initiated by, say, the !quit command) and end the loop
  • recoverable failure states (that just restart the bot)
  • unrecoverable failure states (that end the loop) - I'm not sure if we can differentiate between the two
  • proper restarts (using the !restart command and such)
• optionally logs all of the bot's (console) output, or logs just the sessions where the bot errors out, etc.
• can run the bot as a daemon
• possibly tries to run the bot in a tmux or screen session (but I'm not sure if implementing this can be clean)

We don't need all of that, but a loop that can at least tell apart a !restart or crash/error/whatever and !quit would be really helpful.

We could also provide some init scripts or systemd unit files, but I don't think it's necessary.

[NanoSector]

Possibly we can use this: https://github.com/reactphp/child-process for a PHP script. Systemd unit will be coming up in a bit. Although I'd personally prefer it if the system service manager did this and we didn't implement such thing on our own.

[NanoSector]

Systemd service added as per 612878e

[NanoSector]

I honestly think having a system service manager like systemd handle this is way more reliable than doing it ourselves. I'll leave this open for a while longer.

[ivptr]

The other solution is:
https://github.com/eggheads/eggdrop/blob/develop/scripts/botchk
https://github.com/eggheads/eggdrop/blob/develop/scripts/autobotchk