gto annotate - Must provide artifact path from project root, relative path isn't resolved

[omesser]

When running gto annotate from a subdir with relative file to artifact, that path is taken verbatim to artifacts.yml, which means that unless giving the path from the repo root (might be akward if the current directory is a sub dir, like inside models) the wrong path is saved.

In other words - for safe usage, users must run GTO commands from project root.

Suggested behavior: Identify subdir cwd is on, and where repo root is (assuming artifacts.yaml is always there) - and correct the path - since it always needs to be relative to repo root exactly (not to cwd, and not absolute)