fix(dso): do not eagerly resolve symlinks

This change contains three improvements:

- we use a separate root node, so that it is easier to debug
  what is going on
- we now are able to print the DOT graph of ELF binaries in
  DsoCleaner
- we do not eagerly resolve symlinks, which produced completely
  incorrect results before

src/args.rs

@@ -27,6 +27,11 @@ pub struct Args {
     #[arg(long)]
     pub blocklist: Option<PathBuf>,
 
+    /// An optional path to save the file graph of the DSO cleaner
+    /// in GraphViz format. Useful for debugging.
+    #[arg(long)]
+    pub output_dotfile: Option<PathBuf>,
+
     /// The location of the sysroot to clean up
     pub sysroot_location: PathBuf,
 }