Dedicated server documentation is inaccurate for 4.0

Your Godot version: 4.0

Issue description:

I was trying to set up a new Godot 4.0 project that will use a dedicated game server and while going through the docs I realized that this page needs a bit of an overhaul. As a preface, the server platform was removed from SCons in the following PR and I believe that as a result, any reference to server vs. headless in the documentation is no longer accurate:

https://github.com/godotengine/godot/pull/49074

If I understand that pull request correctly, there is no longer a dedicated server binary and instead any platform can use the --display-driver headless argument.

The Exporting for dedicated servers probably needs a major rework. Some specific issues:

It links to server downloads page which 404s
- I believe this is because server binaries are no longer being built in 4.0 so this downloads page was taken down
The "Headless" vs "server" binaries section is no longer valid
It refers to the godot-server binary
- ./godot-server --main-pack my_project.pck

It seems like the entire workflow for dedicated servers is probably different now? I think a relatively simple recommended flow could be something like:

Add an option like --server to the user's project to be parsed with OS.get_cmdline_user_args() that should be handled such that the project will behave like a server
Export a .PCK file (Same as before)
Run the exported foo.pck file via godot --display-driver headless --main-pack foo.pck -- --server
- This godot executable is the same editor executable for the desired platform

Also, this Introduction to the buildsystem page still refers to the server platform.

I don't mind submitting a PR for these but would like to first verify what the recommended solution is for dedicated servers in 4.0 so I don't write anything inaccurate.

URL to the documentation page:

godotengine / godot-docs

Dedicated server documentation is inaccurate for 4.0 #7310