Add a shorthand method build_arc to builder structs

[SpriteOvO]

Simplify usage.

Before

use std::sync::Arc;

let file_sink = Arc::new(
    RotatingFileSink::builder()
        .base_path(path)
        .rotation_policy(RotationPolicy::Daily { hour: 0, minute: 0 })
        .build()?,
);
let new_logger = Arc::new(Logger::builder().sink(file_sink).build()?);
spdlog::set_default_logger(new_logger);

After

let file_sink = RotatingFileSink::builder()
    .base_path(path)
    .rotation_policy(RotationPolicy::Daily { hour: 0, minute: 0 })
    .build_arc()?;
let new_logger = Logger::builder().sink(file_sink).build_arc()?;
spdlog::set_default_logger(new_logger);