In interactive (user) contexts, use `try_sign` instead of `sign`.
We also revisit the `Profile` by adding a `signer` method that can
fail, eg. if we couldn't connect to ssh-agent.
Finally, we replace `UnsafeSigner` with `MemorySigner`, which makes
use of `ssh::Keystore`.
Signed-off-by: Alexis Sellier <alexis@radicle.xyz>
The changes in this commit are all intertwined and it was hard to
split them into smaller commits:
* Use custom transports everywhere
Instead of `file://` and instead of using a child process for fetching
and pushing; we go through our custom transports, which use the `rad://`
and `heartwood://` schemes.
* Introduce a 'mock' remote transport
To test the remote transport without needing to spawn TCP streams,
we add a mock transport that works between storages on the file
system.
* Get rid of node's `git-url`
Instead of git urls, nodes simply use their node-ids to replicate.
Alexis Sellier