use derive macro for Default trait on Scoreboard struct

[suprohub]

Description

A Detailed Description:
when I was reading the code I accidentally came across this:

impl Default for Scoreboard {
    fn default() -> Self {
        Self::new()
    }
}

In my opinion, this is a useless piece of code, because we can use #[derive(Default)] instead of this, for speed up
code read time.

Testing

cargo run and joining to server

Checklist

Things need to be done before this Pull Request can be merged.

• Code is well-formatted and adheres to project style guidelines: cargo fmt
• Code does not produce any clippy warnings cargo clippy

[Snowiiii]

Looks good.
Thanks @suprohub