refactor(tvix/{cli,store}): move TvixStoreIO to tvix-cli crate

This trait is eval-specific, there's no point in dealing with these
things in tvix-store.

This implements the EvalIO interface for a Tvix store.
The proper place for this glue code (for now) is tvix-cli, which knows
about both tvix-store and tvix-eval.

There's one annoyance with this move: The `tvix-store import` subcommand
previously also used the TvixStoreIO implementation (because it
conveniently did what we wanted).
Some of this code had to be duplicated, mostly logic to calculate the
NAR-based output path and create the PathInfo object.

Some, but potentially more of this can be extracted into helper
functions in a shared crate, and then be used from both TvixStoreIO in
tvix-cli as well as the tvix-store CLI entrypoint.

Change-Id: Ia7515e83c1b54f95baf810fbd8414c5521382d40
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9212
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>

tvix/cli/Cargo.toml

@@ -11,14 +11,15 @@ path = "src/main.rs"
 nix-compat = { path = "../nix-compat" }
 tvix-store = { path = "../store", features = []}
 tvix-eval = { path = "../eval" }
-rustyline = "10.0.0"
+bytes = "1.4.0"
 clap = { version = "4.0", features = ["derive", "env"] }
+data-encoding = "2.3.3"
 dirs = "4.0.0"
+rustyline = "10.0.0"
 smol_str = "0.2.0"
 ssri = "7.0.0"
-data-encoding = "2.3.3"
 thiserror = "1.0.38"
-bytes = "1.4.0"
+tracing = "0.1.37"
 
 [dependencies.wu-manber]
 git = "https://github.com/tvlfyi/wu-manber.git"