Since all signers implement `signature::Keypair`, we can simplify the
implementations of `signature::Signer<ExtendedSignature>`. A blanket
implementation is not possible, because we do not control
`signature::Signer`.
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.
For further details on the crate see its documentation in
`crates/radicle-oid/src/lib.rs`.
Changes to `crates/radicle{,-crypto}/Cargo.toml` are to preserve the
default features of their dependencies `serde` and `schemars`,
which are disabled to support `radicle-oid` being `no_std`.
The `git-ref-format-core` crate is enough to implement everything
required by `radicle-crypto`, and has a much smaller dependency
footprint than `radicle-git-ext`. Notably, it does not depend on
`git2` and also does not depend on procedural macros.
The upgrade of the `radicle-crypto` crate was missed when upgrading
semver versions.
Unfortunately, since it is at the base of the dependency tree, all
crates that depend on it require an additional upgrade.
`radicle-crypto` is the only crate that actually depends on `ssh-key`. I
overlooked that previously and added it as a workspace dependency. Now I
am limiting its scope again.