pxar: add functionality to pass exclude MatchPatterns on create

This exposes the option to pass a list of exclude MatchPattern via the
'--exclude' option.
The list is encoded as file '.pxarexclude-cli' in the archives root directory.
If such a file is present in the filesystem, it is skipped and not included in
the archive in order to avoid conflicting information.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>

tests/catar.rs

@@ -27,7 +27,17 @@ fn run_test(dir_name: &str) -> Result<(), Error> {
     let path = std::path::PathBuf::from(dir_name);
 
     let catalog = None::<&mut catalog::DummyCatalogWriter>;
-    Encoder::encode(path, &mut dir, &mut writer, catalog, None, false, false, flags::DEFAULT)?;
+    Encoder::encode(
+        path,
+        &mut dir,
+        &mut writer,
+        catalog,
+        None,
+        false,
+        false,
+        flags::DEFAULT,
+        Vec::new(),
+    )?;
 
     Command::new("cmp")
         .arg("--verbose")