[lldb][lldb-vscode] Add example configuration for connecting to a remote gdbserver (#68866)

This can be used to have VS Code debug various emulators, remote
systems, hardware probes, etc.

In my case I was doing this for the Gameboy Advance,
https://github.com/stuij/gba-llvm-devkit/blob/main/docs/Debugging.md#debugging-using-visual-studio-code.

It's not very complex if you know LLDB well, but when using another
plugin, CodeLLDB, I was very glad that they had an example for it. So we
should have one too.