Expose easy way to proxy requests through e.g. tor

[daywalker90]

Currently i don't see an easy way to proxy the requests made by this crate through tor. I would like atleast one of DNSHrnResolver or HTTPHrnResolver to expose a proxy option. For HTTPHrnResolver and reqwest you can simply do

reqwest::Client::builder()
            .proxy(proxy)
            .build()?

instead of

reqwest::Client::new()

For DNSHrnResolver it would get a little bit more complicated. You would need changes in dnssec-prover and probably introduce a new dependency for socks5 proxying. I only found crates that work with tokio and none that looked maintained that work without.