adds cli options for spacedust, slingshot, and ufos for binding service port and metrics port #37

[jvalinsky]

The clippy linting has a rule for too_many_arguments set to a max of 7, my refactored serve func for slingshot has 8 args:

pub async fn serve(
    cache: HybridCache<String, CachedRecord>,
    identity: Identity,
    repo: Repo,
    domain: Option<String>,
    acme_contact: Option<String>,
    certs: Option<PathBuf>,
    shutdown: CancellationToken,
    bind: std::net::SocketAddr,
) -> Result<(), ServerError> {

How do you recommend fixing this?