w32: Make gnupg_remove and gnupg_rename_file Unicode aware
* common/sysutils.c (w32_rename): New. (gnupg_rename_file) [W32]: Support Unicode. (gnupg_remove) [W32]: Support Unicode. Drop Windows-CE support.
(cherry picked from commit 9a0197b6fe412cfc66b0cece521267180e454416)
- GnuPG-bug-id: T5098