Add batch del files RPC (#694)

* Add batch del files RPC

* Add pack multi-level files

* Go add pack multi-level files

* Use change set to batch del files

* Improve args

---------

Co-authored-by: 杨赫然 <heran.yang@seafile.com>

server/change-set.h

@@ -0,0 +1,37 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+
+#ifndef SEAF_CHANGE_SET_H
+#define SEAF_CHANGE_SET_H
+
+#include <glib.h>
+#include "utils.h"
+
+struct _ChangeSetDir;
+
+struct _ChangeSet {
+    char repo_id[37];
+    /* A partial tree for all changed directories. */
+    struct _ChangeSetDir *tree_root;
+};
+typedef struct _ChangeSet ChangeSet;
+
+ChangeSet *
+changeset_new (const char *repo_id, SeafDir *dir);
+
+void
+changeset_free (ChangeSet *changeset);
+
+/*
+  @remove_parent: remove the parent dir when it becomes empty.
+*/
+void
+remove_from_changeset (ChangeSet *changeset,
+                       const char *path,
+                       gboolean remove_parent,
+                       const char *top_dir,
+                       int *mode);
+
+char *
+commit_tree_from_changeset (ChangeSet *changeset);
+
+#endif