Adds systemd guide to run a bun application as a daemon

[RaresAil]

What does this PR do?

Adds a guide for using systemd to run a bun application as a daemon

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)

[zjhendryx]

@RaresAil One quick change I would suggest is, you have "User=root" in your systemd file, when going by your guide you likely want that to be the value of YOUR_USER, as it doesn't need to run as root. So it's best to avoid a possible security situation, especially since you have both bun and the application installed in /home/YOUR_USER following your guide.

[RaresAil]

You are right, I will modify that, in copy pasted from my current case because i run the app as root cause i was lazy to give permission to my user to can run the app on port 443 😂

[RaresAil]

@zjhendryx i added that and explain how to allow the non-root user to use the privileged ports

[colinhacks]

Made some fairly heavy edits. I don't think there's much value in re-iterating systemd documentation here—better to provide a minimal guide that is easy to modify and follow.

[colinhacks]

Thanks @RaresAil, this was excellent!

[karimfromjordan]

@RaresAil One quick change I would suggest is, you have "User=root" in your systemd file, when going by your guide you likely want that to be the value of YOUR_USER, as it doesn't need to run as root. So it's best to avoid a possible security situation, especially since you have both bun and the application installed in /home/YOUR_USER following your guide.

Small suggestions, DynamicUser=yes would be even better. systemd will then dynamically allocate a user for you and also enable PrivateTemp, ProtectHome and ProtectSystem automatically.