refactor: Introduce crates folder (#2088)

This PR introduces a new `crates` directory and moves all "product" crates into that folder. 

Part of #2059.

crates/ruff_dev/src/print_cst.rs

@@ -0,0 +1,25 @@
+//! Print the `LibCST` CST for a given Python file.
+#![allow(clippy::print_stdout, clippy::print_stderr)]
+
+use std::fs;
+use std::path::PathBuf;
+
+use anyhow::{bail, Result};
+
+#[derive(clap::Args)]
+pub struct Args {
+    /// Python file for which to generate the CST.
+    #[arg(required = true)]
+    file: PathBuf,
+}
+
+pub fn main(args: &Args) -> Result<()> {
+    let contents = fs::read_to_string(&args.file)?;
+    match libcst_native::parse_module(&contents, None) {
+        Ok(python_cst) => {
+            println!("{python_cst:#?}");
+            Ok(())
+        }
+        Err(_) => bail!("Failed to parse CST"),
+    }
+}