Introduce the `radicle-core` crate for housing data types that are at
the core of the Radicle protocol. The initial data type being added is
`RepoId`. To make the crate as lightweight as possible many of
dependencies are optional and gated by feature flags.
The crate is marked as `no_std` even though it unconditionally depends
on `radicle-crypto`, which is *not* `no_std`. This is to invite
refactoring of `radicle-crypto` to `no_std` at a later time.
The trait `radicle_ssh::agent::client::ClientStream` trait was
simplified, because `winpipe::WinStream` is so similar to
`std::os::unix::net::UnixStream` that we can just use the same
implementation for both platforms.
However, obtaining the process identifier of the SSH agent process is
not common on Windows, so we instead track the path that we used to
connect to the agent. This is also helpful on Unix. In some cases, the
path will even contain the process identifier. The path is printed by
`rad self`.
Errors are cleaned up, and error messages are improved.
Fintan Halpenny
Lorenz Leutgeb