feat(start): Add --detach flag

This will create a dedicated worktree for the instance.

App listed to be enabled will also benefit from their own worktrees.

The worktree is cleanup when the instance is destroyed.

src/args.rs

@@ -525,6 +525,7 @@ fn test_arg_parse() {
         sources_root: Default::default(),
         app_directories: Default::default(),
         work_dir: Default::default(),
+        worktree_dir: Default::default(),
         auto_setup: Default::default(),
         volume: vec![],
         blackfire: None,