vfs_ceph_new: implement DFS hooks using libcephfs low-level APIs

vfs_ceph_new: implement DFS hooks using libcephfs low-level APIs

Refactor the VFS hooks 'create_dfs_pathat_fn' and 'read_dfs_pathat_fn'
in 'vfs_ceph_new.c' to use libcephfs low-level APIs: instead of using
path-based operations (as done in legacy 'vfs_ceph.c') use inode based
operations to create and read msdfs symbolic-links values.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15703

Signed-off-by: Shachar Sharon <ssharon@redhat.com>
Reviewed-by: Anoop C S <anoopcs@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Wed Sep 11 19:09:41 UTC 2024 on atb-devel-224

(cherry picked from commit 0cedd74e47ab919528420761a5bd2acb198f084c)