Move to multi crates project

Starting impl devcontainer spec

crates/devcontainer-rs/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "devcontainer-rs"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+tokio = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+anyhow = { workspace = true }
+thiserror = { workspace = true }
+
+[dev-dependencies]
+tempfile = "3"