Update composefs-setup-root to parse composefs-rs config

Instead of parsing ostree's toml config, we will have and parse
composefs-rs config located at `/usr/lib/composefs/setup-root-conf.toml`

Signed-off-by: Pragyan Poudyal <[email protected]>

Author: Johan-Liebert1

src/bin/composefs-setup-root.rs

@@ -74,7 +74,7 @@ struct Args {
 
     #[arg(
         long,
-        default_value = "/usr/lib/ostree/prepare-root.conf",
+        default_value = "/usr/lib/composefs/setup-root-conf.toml",
         help = "Config path (for testing)"
     )]
     config: PathBuf,