Fetch analysis crate directly from the upstream git

Instead of keeping a copy of analysis, we can fetch it directly from the upstream git repository.

Note that to improve network use, a shallow copy is explicitly used (see .cargo/config.toml).

The latest version of analysis (with a small change to the Cargo.toml) makes cargo a bit buggy due to a weird dependency hole, which may be fixed in a newer version of cargo.

Furthermore, due to the cargo configuration of prusti, cargo must be configured with the -Zbindeps flags (see flake.nix).

rr_frontend/.cargo/config.toml

@@ -210,8 +210,6 @@ rustflags = [
     "-Aclippy::let_unit_value",
 ]
 
-
-# See https://doc.rust-lang.org/1.74.0/nightly-rustc/cargo/core/features/struct.GitoxideFeatures.html
 [unstable.gitoxide]
 checkout = true
 fetch = true