When decoding an input string for a `RepoId`, the base was never checked.
This change ensures that the base is checked and will error otherwise.
To allow for future base codes, the change introduces a sanctioned set
of base codes, which only contains `Base58Btc` for now.
Tests are added to ensure that parsing is correct and includes a valid
multibase code 'Z', which is not the expected 'z'.
Two code fences that do not contain are not marked as such, leading to
false negatives when testing `radicle-core`. To remedy, mark these
fences as text.
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.
Fintan Halpenny
Lorenz Leutgeb
Adrian Duke