feat(cleaners): add main async runner

Adds a Runner able to work upon a set of cleaners that
work in parallel.

src/args.rs

@@ -1,8 +1,23 @@
 // SPDX-FileCopyrightText: Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
 // SPDX-License-Identifier: EUPL-1.2
 
+use std::path::PathBuf;
+
 use clap::Parser;
 
+/// A tool to clean up sysroots for Linux embedded devices to save storage space.
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
-pub struct Args {}
+pub struct Args {
+    /// Simulate operations without carrying them out
+    #[arg(short = 'n', long, default_value_t = false)]
+    pub dry_run: bool,
+
+    /// Instead of simply removing files, move them to the
+    /// given location, preserving their relative folder structure
+    #[arg(long)]
+    pub split_to: Option<PathBuf>,
+
+    /// The location of the sysroot to clean up
+    pub sysroot_location: PathBuf,
+}