Invoking cargo tomlfmt on all files is a PITA and as we can see from
the CI scripts, it is often forgotten to as new crates are added to
the workspace.
Using dprint for toml files fixes this.
Unfortunately, we can't use dprint for Rust code yet because there
hasn't been a release of rustfmt in quite a while but we are already
using features from a newer rustfmt via rustup.
1. `monero-rpc` is not in the position to decide about the TLS backend
an application should use.
2. We don't use TLS encrypted communication to my knowledge so we don't
have to activate this feature anywhere else.
