Consider using `rustls` as default instead of `native-tls`

Currently we default to native-tls instead of rustls. I'd like to open a discussion to determine if this is the correct approach.

First I am curious to why we decided to default to native-tls.

Then I'd like to list some advantages of rustls:

More secure (Rust code, doesn't use insecure TLS versions,...)
If a user's system has compromised root certificates, Arti would use it when using native-tls?
rustls is more portable (I personally often encounter issues when using Arti libraries with native-tls while they work fine with rustls).

Considering this, isn't rustls more suitable as default TLS library instead of native-tls?

Issue created regarding: !2941 (comment 3222879)

Consider using rustls as default instead of native-tls